To answer that question in just one sentence: A Christian is a disciple (that is, a follower) of Jesus Christ. Here’s what that means:
1. Christians fear God.
No one will seek safety if he does not believe he is in danger. Christians have come to understand that God is holy and just, as well as powerful. They have come to see that people, in their natural state, are rebellious and sinful (John 3:19-20). Christians understand that God must judge sinners and destroy all who remain His enemies. He would not be just if He did not do so. They also understand that all people, being naturally rebellious, deserve to be destroyed. And Christians know that God will have no difficulty destroying His enemies. Being all-powerful, He is easily able to do so (Psalm 2; Hebrews 12:29).
2. Christians believe in Jesus, who alone provides salvation.
Christians trust Jesus alone for salvation (John 14:6; Acts 4:12). They know that only Jesus paid God’s required penalty for sin—the penalty of death (1 Peter 3:18; Hebrews 10:11-14). They understand that Jesus, who never sinned even though tempted (Hebrews 4:15), was publicly executed, having his hands and feet nailed to a wooden cross, finishing the work of atonement (John 19:30). They understand that after His death and resurrection, Jesus presented Himself to His Father in heaven as the one and only acceptable sacrifice for sin (Hebrews 7:27; 9:12).
3. Christians believe and value God’s Word.
A person is not a Christian if he does not believe God. God’s words are found in only one place—the Bible. Anyone who does not believe the Bible to be God’s Word is not a Christian. Neither is the one who says the Bible is the Word of God, but does not believe all of it. Christians believe God even when the things He has said are supernaturally amazing or hard to understand.
Christians see God’s Word not only as true, but also as beautiful, valuable, excellent, and authoritative. According to Paul, God’s message of salvation is “the fragrance of Christ” to those who are being saved (2 Corinthians 2:15). Jesus said, “If you abide [remain, or live] in My word, you are My disciples indeed” (John 8:31). And David tells us that God has magnified His Word above His name (Psalm 138:2). No one who is disinterested in God’s Word can rightly claim to love God Himself.
4. Christians love God and others.
Jesus said the greatest command is to love God with all your heart, soul, mind, and strength (Mark 12:32). Paul tells us that anyone who does not love the Lord Jesus Christ is to be accursed (1 Corinthians 16:22). A Christian, then, is one who loves God.
True Christians also love other Christians. There is no such thing as a Christian who does not love his brothers and sisters in Christ (John 13:34-35; 1 John 3:10; 4:8). And Christians treat non-Christians—even those who persecute them—with kindness and generosity. In this they imitate God their Father, who gives even His enemies good things (Matthew 5:43-48).
5. Christians have rejected self-righteousness.
They know that no amount of good deeds, righteous living, or religious activity could ever please God apart from faith in Jesus Christ (cf. Romans 3:28; 4:1-8; Galatians 2:15-16; 21; Titus 3:5-7). They have come to understand that all such attempts are nothing more than repulsive demonstrations of human pride (Isaiah 64:6). Religious activity apart from genuine faith in Christ is actually one of the clearest evidences that a person is still God’s enemy. The idea that a fallen human being could attain to God’s required standard of righteousness is not only an insult to God, it calls Him a liar since He has said that there are none who are righteous (cf. Romans 3:10-12). Christians, therefore, have given up on self-righteousness and rest only in the righteousness of their Savior, Jesus Christ.
6. Christians acknowledge and submit to Christ’s authority.
Christians know that Jesus, who died for their sins and rose from the grave, holds ultimate authority over them, and over all things (Ephesians 2:22). Recognizing His authority and loving Him for His goodness and mercy, they seek with all their heart to obey Him. As Jesus said, “If you love Me, you will obey My commandments.” (John 14:15; 1 John 2:3-4). Among those who claim to be followers of Jesus, repentance and obedience are the inevitable marks of all true Christians.
In summary, Christians are people who believe God. They have abandoned all hope in any solution other than Jesus Christ. They fear God reverently and cherish His Word. Their highest affection in life is for God, for Jesus Christ, and for the many others who are His. Even while maintaining a proper and necessary separation from this fallen world (cf. 2 Corinthians 6:14-18), their stance toward unbelievers is one of kindness, compassion, and prayerful concern.
So: Are you a Christian?