What Is A Christian?
There seems to be many answers among Christians to this crucial question. In this study we will take a look at what the Bible says a Christian is.
Connected Bible studies:
Testing The Spirits
The Word Of The Cross
The Jehoiada Priesthood
Evidence Of The Holy Spirit
The following definitions for a Christian are from Nelson's Illustrated Bible Dictionary and Vine's Expository Dictionary of Biblical Words.
An adherent or follower of Christ. The word occurs three times in the New Testament: "The disciples were first called Christians in Antioch" (Acts 11:26); Agrippa said to Paul, "You almost persuade me to be a Christian" (Acts 26:28); Peter exhorted, "If anyone suffers as a Christian, let him not be ashamed" (1 Peter 4:16). In each instance, the word Christian assumes that the person called by the name was a follower of Christ. Christians were loyal to Christ, just as the Herodians were loyal to Herod (Matt. 22:16; Mark 3:6; 12:13).
The designation of the early followers of Christ as Christians was initiated by the non-Christian population of Antioch. Originally it may have been a term of derision. Eventually, however, Christians used it of themselves as a name of honor, not of shame. Prior to their adoption of the name, the Christians called themselves believers (Acts 5:14), brothers (Acts 6:3), or saints (Acts 9:13), names which also continued to be used.
In modern times the name Christian has been somewhat emptied of its true meaning as a follower of Christ. To some today, Christian means little more than a European or American who is not Jewish, while others have sought to make its proper use the name of a particular denomination. However, its original meaning is a noble one, of which any follower of Christ can rightly be proud.
(Nelson's Illustrated Bible Dictionary - copyright (C) 1986, Thomas Nelson Publishers)
christianos , "Christian," a word formed after the Roman style, signifying an adherent of Jesus, was first applied to such by the Gentiles and is found in Acts 11:26; 26:28; 1 Peter 4:16.
Though the word rendered "were called" in Acts 11:26 it might be used of a name adopted by oneself or given by others, the "Christians" do not seem to have adopted it for themselves in the times of the apostles. In 1 Peter 4:16, the apostle is speaking from the point of view of the persecutor, cf. "as a thief," "as a murderer." Nor is it likely that the appellation was given by Jews. As applied by Gentiles there was no doubt an implication of scorn, as in Agrippa's statement in Acts 26:28. Tacitus, writing near the end of the first century, says, "The vulgar call them Christians. The author or origin of this denomination, Christus, had, in the reign of Tiberius, been executed by the procurator, Pontius Pilate" (Annals xv. 44). From the second century onward the term was accepted by believers as a title of honor.
(Vine's Expository Dictionary of Biblical Words - copyright (C) 1985, Thomas Nelson Publishers)
Acts 11:19-26 - This is the first time the word “Christian” appears in the New Testament. (See the note below.)
19 So then those who were scattered because of the persecution that arose in connection with Stephen made their way to Phoenicia and Cyprus and Antioch, speaking the word to no one except to Jews alone.
20 But there were some of them, men of Cyprus and Cyrene, who came to Antioch and began speaking to the Greeks also, preaching the Lord Jesus.
21 And the hand of the Lord was with them, and a large number who believed turned to the Lord.
22 And the news about them reached the ears of the church at Jerusalem, and they sent Barnabas off to Antioch.
23 Then when he had come and witnessed the grace of God, he rejoiced and began to encourage them all with resolute heart to remain true to the Lord;
24 for he was a good man, and full of the Holy Spirit and of faith. And considerable numbers were brought to the Lord.
25 And he left for Tarsus to look for Saul;
26 and when he had found him, he brought him to Antioch. And it came about that for an entire year they met with the church, and taught considerable numbers; and the disciples were first called Christians  in Antioch.
5546 Christianos (khris-tee-an-os')
from 5547 [see the definition below]; a Christian, i.e. follower of Christ:
5547 Christos (khris-tos')
from 5548 [see the definition below]; anointed, i.e. the Messiah, an epithet of Jesus:
5548 chrio (khree'-o)
(Strong’s Exhaustive Concordance)
probably akin to 5530 through the idea of contact; to smear or rub with oil, i.e. (by implication) to consecrate to an office or religious service, to anoint:
(Thayer’s Greek Lexicon)
a) consecrating Jesus to the Messianic office, and furnishing him with the necessary powers for its
b) enduing Christians with the gifts of the Holy Spirit
This is the first time the word “Christian” appears in the New Testament. By definition (see below), a Christian is a “follower of Christ.” Because of close contact with Jesus (see  below), He has “rubbed off,” so to speak, on them. The anointing oil of the Holy Spirit has endued them with power for the administration of the Lord’s Messianic office in their life. You will know them because they have begun to look and act to one degree or another as their Lord, with whom they have become close by choice. You will also know them by the fruits of the Holy Spirit that have been developed in their lives (see Galatians 5:16-25 below). Saying you are a Christian is not enough to make you one. Being a Christian is not in word only, but rather in deed and character. We become like that which we follow, or are the closest to, whether that be the world, or the Lord Jesus Christ.
Matthew 4:18-22- The disciples call from Jesus; “Come here! Come Now!" True disciples hear His voice to come and obediently follow. I believe these men’s hearts had been prepared so that, when Jesus came near and called out to them, they were ready to go, leaving everything behind. One day, as Jesus and His disciples were walking along, one of them said to Him, “I will follow you wherever you go.” Jesus replied, “Foxes have holes and birds of the air have nests, but the Son of Man has no place to lay his head.” He seemed to imply that to follow Him is to walk a difficult way of life at times. He said to another man, “Follow me.” But the man replied, “Lord, first let me go and bury my father.” Jesus said to him, “Let the dead bury their own dead, but you go and proclaim the kingdom of God.” Still another said, “I will follow you, Lord; but first let me go back and say good-by to my family.” Jesus replied, “No one who puts his hand to the plow and looks back is fit for service in the kingdom of God.” (Luke 9:57-62/NIV, Matthew 8:19-23) These are difficult statements, for sure, but all pointing to the necessity of not looking back when following Christ. Remember Lot’s wife… (Luke 17:32 which refers to Genesis 19:26).
18 And walking by the Sea of Galilee, He saw two brothers, Simon who was called Peter, and Andrew his brother, casting a net into the sea; for they were fishermen.
19 And He said to them, "Follow [the Greek means “Come here! Come now!”] Me, and I will make you fishers of men."
20 And they immediately left the nets, and followed Him.
21 And going on from there He saw two other brothers, James the son of Zebedee, and John his brother, in the boat with Zebedee their father, mending their nets; and He called them.
22 And they immediately left the boat and their father, and followed Him.
Matthew 9:9- Matthew’s call to come follow Jesus.
9 And as Jesus passed on from there, He saw a man, called Matthew, sitting in the tax office; and He said to him, "Follow Me!" And he rose, and followed Him.
Matthew 10:24-39 - Denying Christ before men and its consequences. Jesus’ definition of what it means to be a follower of Him.
32 "Everyone therefore who shall confess [“to declare openly”] Me before men, I will also confess him before My Father who is in heaven.
33 "But whoever shall deny [“to contradict”] Me before men, I will also deny him before My Father who is in heaven. [See the Bible study Testing The Spirits.]
34 "Do not think that I came to bring peace on the earth; I did not come to bring peace, but a sword.
35 "For I came to set a man against his father, and a daughter against her mother, and a daughter-in-law against her mother-in-law;
36 and a man's enemies will be the members of his household.
37 "He who loves father or mother more than Me is not worthy of Me; and he who loves son or daughter more than Me is not worthy of Me.
38 "And he who does not take his cross and follow after Me is not worthy of Me.
39 "He who has found his life shall lose it, and he who has lost his life for My sake shall find it.
Matthew 16:24-26- The terms of following Jesus.
24 Then Jesus said to His disciples, "If anyone wishes to come after Me, let him deny himself, and take up his cross, and follow Me.
25 "For whoever wishes to save his life shall lose it; but whoever loses his life for My sake shall find it.
26 "For what will a man be profited, if he gains the whole world, and forfeits his soul? Or what will a man give in exchange for his soul?
A Christian’s life will be one of self-denial. He will be walking the walk of death to himself, his desires, like his Savior did while on earth in a human body (see the Bible study The Word Of The Cross), so that Christ’s life can flow unhindered within and then without us. When they disobey, which we all do at one time or another, they repent. The Holy Spirit will continually lead you through this lifelong process called sanctification (see the Bible studies Glorified and Consecration). It will be the revealing of something within your heart (your natural affections and desires) that must be brought under His control. This is referred to by Paul in the New Testament as “walking in the Spirit.” Galatians 5:24-25 says; "Now those who belong to Christ Jesus have crucified the flesh with its passions and desires. If we live by the Spirit, let us also walk by the Spirit."
The resurrected Jesus said to Peter in John 21:18-19 before His ascension; “Truly, truly, I say to you, when you were younger, you used to gird yourself, and walk wherever you wished; but when you grow old, you will stretch out your hands, and someone else will gird you, and bring you where you do not wish to go.” Now this He said, signifying by what kind of death he would glorify God. And when He had spoken this, He said to him, “Follow me!”
Again, the Holy Spirit will bring our sinful nature to a place of death where it naturally will not wish to go. But as we decrease, He will increase within us (see John 3:30). He fills the space that has been made available for Him. A 3/4 full glass can only be filled 1/4 of the way with something else. The greater the depth of joining Christ in His cross, the greater the revelation of His glory within will be. Romans 8:17-18 says; "Now if we are children, then we are heirs-- heirs of God and co-heirs with Christ, if [I refer to these as “big ifs” that are found throughout the New Testament] indeed we share in his sufferings in order that we may also share in his glory. I consider that our present sufferings are not worth comparing with the glory that will be revealed in us." This is the pattern revealed through Jesus’ life; something is brought to death in order to gain God’s glory.
Matthew 19:16-30- Terms to the rich man with a promise.
21 Jesus said to him, "If you wish to be complete, go and sell your possessions and give to the poor, and you shall have treasure in heaven; and come, follow me."
22 But when the young man heard this statement, he went away grieved; for he was one who owned much property.
27 Then Peter answered and said to Him, "Behold, we have left everything and followed You; what then will there be for us?"
28 And Jesus said to them, "Truly I say to you, that you who have followed Me, in the regeneration when the Son of Man will sit on His glorious throne, you also shall sit upon twelve thrones, judging the twelve tribes of Israel.
29 "And everyone who has left houses or brothers or sisters or father or mother or children or farms for My name's sake, shall receive many times as much, and shall inherit eternal life.
30 "But many who are first will be last; and the last, first.
Mark 8:34-38- To follow Christ means to disassociate from our own desires and interests (to deny), and then to take up our cross as Christ did, never to come back to the way things were. Forgetting what lies behind, you press on to take hold of that for which Christ took hold of you (Phil. 3:12-15). See the Bible study Joined Together regarding the necessary separation from the old way of life and relationships that would keep us from being fully joined to Christ as “one,” as pictured in marriage.
34 And He summoned the multitude with His disciples, and said to them, "If anyone wishes to come after Me, let him deny  himself, and take up [“to take upon oneself and carry what has been raised up”] his cross, and follow Me.
35 "For whoever wishes to save his life shall lose it; but whoever loses his life for My sake and the gospel's shall save it.
36 "For what does it profit a man to gain the whole world, and forfeit his soul?
37 "For what shall a man give in exchange for his soul?
38 "For whoever is ashamed of Me and My words in this adulterous and sinful generation, the Son of Man will also be ashamed of him when He comes in the glory of His Father with the holy angels."
533 aparneomai (ap-ar-neh'-om-ahee)
(Strong’s Exhaustive Concordance)
from 575 and 720; to deny utterly, i.e. disown, abstain
(Thayer’s Greek Lexicon)
a) to affirm that one has no acquaintance or connection with someone
b) to forget oneself, lose sight of oneself and one's own interests
Luke 14:25-35- More instructions for the follower of Jesus. This involves loving Christ above all else, calculating the cost involved, and giving up your right to all your possessions. Does this mean you sell all and live on the street? Some will be called to places around the globe, or even in their own nation, where this will occur. Each Christian will have to seek the Lord’s will for them. In either case it is a decision of the heart to give up the right to claim our possessions as ours and ours alone. If the Lord has need of it, for whatever purpose, we are to already have decided in our hearts that it is His to do with it as He wills. We are simply stewards. I find my flesh fighting this at times.
25 Now great multitudes were going along with Him; and He turned and said to them,
26 "If anyone comes to Me, and does not hate his own father and mother and wife and children and brothers and sisters, yes, and even his own life, he cannot be My disciple.
27 "Whoever does not carry his own cross and come after Me cannot be My disciple.
28 "For which one of you, when he wants to build a tower, does not first sit down and calculate the cost, to see if he has enough to complete it?
29 "Otherwise, when he has laid a foundation, and is not able to finish, all who observe it begin to ridicule him,
30 saying, 'This man began to build and was not able to finish.'
31 "Or what king, when he sets out to meet another king in battle, will not first sit down and take counsel whether he is strong enough with ten thousand men to encounter the one coming against him with twenty thousand?
32 "Or else, while the other is still far away, he sends a delegation and asks terms of peace.
33 "So therefore, no one of you can be My disciple who does not give up all his own possessions.
34 "Therefore, salt is good; but if even salt has become tasteless, with what will it be seasoned?
35 "It is useless either for the soil or for the manure pile; it is thrown out. He who has ears to hear, let him hear."
John 10:1-5- The true sheep of the Lord follow Him because they know His voice. They simply will not follow the voice of the false shepherd. In time, a new Christian must learn to recognize and then obey the voice of God. As with any relationship this takes time, but is crucial so as not to be led astray by the enemy’s false voice. If I’m not sure I wait for confirmation which He always gives me. Each time it becomes clearer whose voice is speaking. My wife and I use the peace of God within us as a determining factor (Colossians 3:15). If one of us has a lack of peace in regards to a decision or situation we wait to see why. The Lord has been faithful to always reveal the truth, either way.
1 "I tell you the truth, the man who does not enter the sheep pen by the gate, but climbs in by some other way, is a thief and a robber.
2 The man who enters by the gate is the shepherd of his sheep.
3 The watchman opens the gate for him, and the sheep listen to his voice. He calls his own sheep by name and leads them out.
4 When he has brought out all his own, he goes on ahead of them, and his sheep follow him because they know his voice.
5 But they will never follow a stranger; in fact, they will run away from him because they do not recognize a stranger's voice."
John 10:27-29- A continuation of the above verses.
27 "My sheep hear My voice, and I know them, and they follow Me;
28 and I give eternal life to them, and they shall never perish; and no one shall snatch them out of My hand.
29 "My Father, who has given them to Me, is greater than all; and no one is able to snatch them out of the Father's hand.
John 12:25-26- The true servant of the Lord follows Him to wherever He leads.
25 "He who loves his life loses it; and he who hates his life in this world shall keep it to life eternal.
26 "If anyone serves Me, let him follow Me; and where I am, there shall My servant also be; if anyone serves Me, the Father will honor him.
John 13:36-38- Jesus knew the true condition of Peter’s heart, as He does each one of His follower’s. There have been times when He has had to show me the truth of my confessions that were really not as spoken. He does this out of love to show me the truth of my commitment, where it really is and where I need to change.
36 Simon Peter said to Him, "Lord, where are You going?" Jesus answered, "Where I go, you cannot follow Me now; but you shall follow later."
37 Peter said to Him, "Lord, why can I not follow You right now? I will lay down my life for You."
38 Jesus answered, "Will you lay down your life for Me? Truly, truly, I say to you, a cock shall not crow, until you deny Me three times.
John 21:18-22- As I stated above, the Holy Spirit will bring our sinful nature to a place of death where it naturally will not wish to go. But as we decrease, He will increase within us (see John 3:30). He fills the space that has been made available for Him. A 3/4 full glass can only be filled 1/4 of the way. The greater the depth of joining Christ in His cross, the greater the revelation of His glory within will be. Romans 8:17-18 says; "Now if we are children, then we are heirs-- heirs of God and co-heirs with Christ, if indeed we share in his sufferings in order that we may also share in his glory. I consider that our present sufferings are not worth comparing with the glory that will be revealed in us."
18 "Truly, truly, I say to you, when you were younger, you used to gird yourself, and walk wherever you wished; but when you grow old, you will stretch out your hands, and someone else will gird you, and bring you where you do not wish to go."
19 Now this He said, signifying by what kind of death he would glorify God. And when He had spoken this, He said to him, "Follow me!"
20 Peter, turning around, saw the disciple whom Jesus loved following them; the one who also had leaned back on His breast at the supper, and said, "Lord, who is the one who betrays You?"
21 Peter therefore seeing him said to Jesus, "Lord, and what about this man?"
22 Jesus said to him, "If I want him to remain until I come, what is that to you? You follow Me!"
Matthew 7:13-27- If you claim to be a Christian, you will be doing the will of the Father (obedience) and not practicing lawlessness, or sin. This is how you can tell who is and who is not, by the fruit of their lives. What is being produced will prove where our allegiance truly is. (See the Bible study or book Many Are Called.)
13 "Enter by the narrow gate; for the gate is wide, and the way is broad that leads to destruction, and many are those who enter by it.
14 "For the gate is small, and the way is narrow that leads to life, and few are those who find it.
15 "Beware of the false prophets, who come to you in sheep's clothing, but inwardly are ravenous wolves.
16 "You will know them by their fruits. Grapes are not gathered from thorn bushes, nor figs from thistles, are they?
17 "Even so, every good tree bears good fruit; but the bad tree bears bad fruit.
18 "A good tree cannot produce bad fruit, nor can a bad tree produce good fruit.
19 "Every tree that does not bear good fruit is cut down and thrown into the fire.
20 "So then, you will know them by their fruits.
21 "Not everyone who says to Me, 'Lord, Lord,' will enter the kingdom of heaven; but he who does the will of My Father who is in heaven.
22 "Many will say to Me on that day, 'Lord, Lord, did we not prophesy in Your name, and in Your name cast out demons, and in Your name perform many miracles?'
23 "And then I will declare to them, 'I never knew you [a lack of intimacy from someone who never truly drew close in practice]; depart from Me, you who practice lawlessness.'
24 "Therefore everyone who hears these words of Mine, and acts upon them, may be compared to a wise man, who built his house upon the rock.
25 "And the rain descended, and the floods came, and the winds blew, and burst against that house; and yet it did not fall, for it had been founded upon the rock.
26 "And everyone who hears these words of Mine, and does not act upon them, will be like a foolish man, who built his house upon the sand.
27 "And the rain descended, and the floods came, and the winds blew, and burst against that house; and it fell, and great was its fall."
1 Corinthians 3:1-4- Who are we really following? Yes, we are in covenant with Christ AND His body which is all other believers, but we are to follow Christ’s lead. He is the head. There are times when other Christians do not seem to be leading where we sense Christ desires for us, or others, to go. It is at that point that we are to seek Him and ask for clear direction which He will always give. The Lord’s will is what we need to be following.
1 Brothers, I could not address you as spiritual but as worldly-- mere infants in Christ.
2 I gave you milk, not solid food, for you were not yet ready for it. Indeed, you are still not ready.
3 You are still worldly. For since there is jealousy and quarreling among you, are you not worldly? Are you not acting like mere men?
4 For when one says, "I follow Paul," and another, "I follow Apollos," are you not mere men?
1 Corinthians 11:1- Paul gives the order of following in this passage. We follow Jesus example for others to see Him. Our lives should be lived in such a way as to lead others to follow Jesus.
1 Follow my example, as I follow the example of Christ.
Galatians 5:16-25- The fruit of our sinful natures (flesh) vs. the fruit of the Holy Spirit. If we continue to practice the desires of the flesh (our fallen, corrupt natures that have no intent in submitting to the will of God), with no desire for repentance, we will not enter the kingdom of God. A changed life by the Holy Spirit is proof that we truly are a Christian.
16 But I say, walk by the Spirit, and you will not carry out the desire of the flesh.
17 For the flesh sets its desire against the Spirit, and the Spirit against the flesh; for these are in opposition to one another, so that you may not do the things that you please.
18 But if you are led by the Spirit, you are not under the Law.
19 Now the deeds of the flesh are evident, which are: immorality, impurity, sensuality,
20 idolatry, sorcery, enmities, strife, jealousy, outbursts of anger, disputes, dissensions, factions,
21 envying, drunkenness, carousing, and things like these, of which I forewarn you just as I have forewarned you that those who practice such things shall not inherit the kingdom of God.
22 But the fruit of the Spirit is love, joy, peace, patience, kindness, goodness, faithfulness,
23 gentleness, self-control; against such things there is no law.
24 Now those who belong to Christ Jesus have crucified the flesh with its passions and desires.
25 If we live by the Spirit, let us also walk by the Spirit.
James 1:12- A Christian remains faithful to the Lord when he is tested. In so doing, he will receive life from the Lord. When he falters (which we all do to one degree or another, especially as a new Christian), or stumbles, he will repent. The trials the Lord allows us to go through prove the genuineness of our faith. It reveals our weaknesses that need to be strengthened in the Lord. Trials are God’s quality control.
12 Blessed is a man who perseveres [“to hold fast, to remain, to bear”] under trial [“temptations, a putting to proof”]; for once he has been approved [“proved, tried”], he will receive the crown of life, which the Lord has promised to those who love Him.
1 Peter 1:6-9- It is sometimes necessary for the Lord to allow various trials and temptations to come our way in order to reveal the level of our faith. It shows us (as He already knows) where we really are. A faith that hasn't been tested cannot be trusted.
6 In this you greatly rejoice, even though now for a little while, if necessary, you have been distressed by various trials,
7 that the proof [“genuineness, trustworthiness”] of your faith, being more precious than gold which is perishable, even though tested by fire, may be found to result in praise and glory and honor at the revelation of Jesus Christ;
8 and though you have not seen Him, you love Him [which is proven by our faithfulness], and though you do not see Him now, but believe in Him, you greatly rejoice with joy inexpressible and full of glory,
9 obtaining as the outcome of your faith the salvation of your souls.
James 1:2-4- The testing of our faith is to mature us in the Lord. As I said earlier, it produces perseverance. Without perseverance we will never stand firm till the end and be saved (Math. 10:22, 24:13). A new Christian will learn to understand that experiencing trials in your life does not mean something is wrong, unless the Holy Spirit reveals it to be otherwise. It is actually the normal process that every Christian goes through so as to conform us to the image of Jesus. The rough edges of our characters must be revealed in order to be removed. Trials bring them out in the open. It’s the pruning of the heart that all followers of Jesus must go through.
2 Consider it all joy, my brethren, when you encounter various trials,
3 knowing that the testing of your faith produces endurance [“perseverance, patience”].
4 And let endurance have its perfect result, that you may be perfect and complete, lacking in nothing.
James 1:21-25- A Christian is a doer of the word of God, not just a hearer. He abides in the “law of liberty.” True liberty is that which Christ gives us within. A person could be living in a “free” country and still be a prisoner to the sin that controls him from within. There is a promise of God’s blessing over this person as well in whatever they do.
21 Therefore putting aside all filthiness and all that remains of wickedness, in humility receive the word implanted, which is able to save your souls. [Sin hinders the work, the purpose, or progress of the “living word” within us. This is the ministry of the Holy Spirit. See Romans 1:18-19 concerning “suppressing the truth in unrighteousness”.]
22 But prove yourselves doers of the word, and not merely hearers who delude themselves.
23 For if anyone is a hearer of the word and not a doer, he is like a man who looks at his natural face in a mirror;
24 for once he has looked at himself and gone away, he has immediately forgotten what kind of person he was.
25 But one who looks intently at the perfect law, the law of liberty, and abides by it, not having become a forgetful hearer but an effectual doer, this man shall be blessed in what he does [God’s promise!].
The Testimony, The Witness
(This portion is taken from the Bible study The Jehoiada Priesthood. It is also included in Evidence Of The Holy Spirit.)
2 Chronicles 23:11- In this passage the “testimony”, the “witness” is given to the king’s son, Joash. Our testimony is the witness of Christ that is given to us. The witness is His Holy Spirit poured out within our hearts. The “testimony” (see Vine’s definition below) was also placed within the Ark of the Covenant. The Lord told Moses in Exodus 25:16; "And you shall put into the ark (of the covenant) the testimony which I shall give you." It was also called, the “Ark of the Testimony.”
11 Then they brought out the king's son and put the crown on him, and gave him the testimony , and made him king. And Jehoiada and his sons anointed him and said, "Long live the king!"
2 Chronicles 23:11- The NIV version of the same verse.
11 Jehoiada and his sons brought out the king's son and put the crown on him; they presented him with a copy of the covenant  and proclaimed him king. They anointed him and shouted, "Long live the king!"
5715 `eduwth (ay-dooth')
(Strong’s Exhaustive Concordance)
feminine of 5707 [see definition below]; testimony:
KJV-- testimony, witness.
5707 `ed (ayd)
(Strong’s Exhaustive Concordance)
contracted from 5749 [see definition below] concretely, a witness; abstractly, testimony; specifically, a recorder, i.e. prince:
(Brown Driver Briggs Hebrew Lexicon)
a) witness, testimony, evidence (used of things)
b) witness (used of people)
5749 `uwd (ood)
(Strong’s Exhaustive Concordance)
a primitive root; to duplicate or repeat; by implication, to protest, testify (as by reiteration); intensively, to encompass, restore (as a sort of reduplication):
(Brown Driver Briggs Hebrew Lexicon)
1) to return, to repeat, to go about, to do again
a) (Piel) to surround, to go round and round
b) (Pilel) to restore, to relieve
c) (Hithpalel) to be restored
2) to bear witness
a) (Qal) to bear witness, to say again and again
1) to testify, to bear witness
2) to cause to testify, to take or to call as witness, to invoke
3) to protest, to affirm solemnly, to warn, to exhort or enjoin solemnly, to admonish, to charge
c) (Hophal) to protest, to give warning
This word refers to the Ten Commandments as a solemn divine charge or duty. In particular, it represents those commandments as written on the tablets and existing as a reminder and "testimony" of Israel's relationship and responsibility to God: "And he gave unto Moses, when he had made an end of communing with him upon Mount Sinai, two tables of testimony, tables of stone, written with the finger of God" (Exodus 31:18). Elsewhere these tablets are called simply "the testimony" (Exodus 25:16). Since they were kept in the ark, it became known as the "ark of the testimony" (Exodus 25:22) or simply "the testimony": "As the Lord commanded Moses, so Aaron laid it up before the Testimony, to be kept" (Exodus 16:34)-- the first biblical occurrence of the word. The tabernacle as the housing for the ark containing these tablets was sometimes called the "tabernacle of testimony" (Exodus 38:21) or the "tent of the testimony" (Numbers 9:15).
(from Vine's Expository Dictionary of Biblical Words - copyright (C) 1985, Thomas Nelson Publishers)
1 John 5:10-13- The “witness” of Christ is within us.
10 The one who believes in the Son of God has the witness  in himself; the one who does not believe God has made Him a liar, because he has not believed in the witness that God has borne concerning His Son.
11 And the witness is this, that God has given us eternal life, and this life is in His Son.
12 He who has the Son has the life; he who does not have the Son of God does not have the life.
13 These things I have written to you who believe in the name of the Son of God, in order that you may know that you have eternal life.
3141 marturia (mar-too-ree'-ah)
(Strong’s Exhaustive Concordance)
from 3144; evidence given (judicially or genitive case)
KJV-- record, report, testimony, witness.
(Thayer’s Greek Lexicon)
1) a testifying; the office committed to the prophets of testifying concerning future events
2) what one testifies, testimony, that is, before a judge
This is the evidence of the Holy Spirit within us (see the Bible study called Evidence Of The Holy Spirit). The life of Jesus is duplicated (see  definition above) within us. People will only see Jesus when they see Him in and through us. John 1:4-9 says; "In Him was life, and the life was the light of men. And the light shines in the darkness, and the darkness did not comprehend it. There came a man, sent from God, whose name was John. He came for a witness, that he might bear witness  of the light, that all might believe through him. He was not the light, but came that he might bear witness  of the light. There was the true light which, coming into the world, enlightens every man.”
Revelation 19:10- The “testimony” of Jesus, the witness of Him within, is the spirit of prophecy. Another witness, or evidence of Jesus being within someone is the words of God that they speak. John 3:32-34 says; "What He has seen and heard, of that He bears witness ; and no man receives His witness . He who has received His witness  has set his seal to this, that God is true. For He whom God has sent speaks the words [4487- rhema- “the living word having a definite meaning”] of God; for He gives the Spirit [the evidence, the witness, the testimony] without measure."
10 And I fell at his feet to worship him. And he said to me, "Do not do that; I am a fellow servant of yours and your brethren who hold [2192- “to have, that is, to hold; to own, to possess”] the testimony  of Jesus; worship God. For the testimony  of Jesus is the spirit of prophecy."