That is a good question! You might feel bewildered by the answers these days. The United States is supposed to be a “Christian country.” Many people claim to be Christians: perhaps you are one of them. “I’m a Roman Catholic…” “I’ve been confirmed in Church and gone all my life.” “I was brought up in church, and I never do anybody any harm.”
Authority
It’s strange how we want to be our own authority concerning religion. With any other subject, we feel out of our depth and need some recognized authority to tell us. But with religious belief, “what I think” seems to be enough. I cannot imagine us doing the same with, say, a worrying pain in our left side. “What I think” is no safe guide to whether its indigestion or heart pain or cancer. Therefore, we consult the doctor — if anyone can sort it out, he can, or a specialist to whom he may refer me. Why, then, be any different when it comes to what real Christianity is? “So, you reckon I have to trust a church minister to tell me?” Not necessarily. There is an authority higher than any of us, and that is the Bible. Any Christian minister who bases his answer on that Book can be trusted. But we can read the Bible for ourselves.
Need
The Bible tells us that a Christian is someone who has felt a real need. He has been “convinced of sin” (John 16:8). Christianity is not a hobby or just a way of life. It is rescue, salvation. It stems from a God-given realization that we have been life-long rebels against God, broken His laws and have offended His holy majesty. It does not begin by being good enough, but by realizing that we are very bad. Then we are prepared for the provision of God’s forgiveness and new life through Jesus Christ. Without this sense of need, there is no concern to receive Christ and be saved.
You may read this as someone indifferent and unconcerned. And you may think this disproves Christianity. Quite the reverse. Your lack of any felt need simply confirms what the Bible teaches: that we are all like this until God awakens us to see ourselves as we really are. Then we are ready to appreciate the saving power of Jesus Christ. “They that are whole have no need of a physician, but they that are sick” (Matthew 9:12).
Understanding
A Christian is also one who has a new understanding. He realizes why Jesus Christ came into the world, died on the Cross and rose again from the dead. It was to save — to rescue — guilty, hell-deserving sinners. He “died for the ungodly” … “died for our sins” … “suffered once for sins, the just for the unjust, that he might bring us to God” (Romans 5:9; 1 Corinthians 15:3; 1 Peter 3:18). To those who understand their need, this Gospel message is good news: it means that Jesus has taken all our obligations and failures, all our sins and their punishment, upon Himself. He accepted the full consequences of them. That meant the horrific agonies of crucifixion and the wrath of a holy, sin-hating God, suffering a penal death and hell in our place. Such a person exclaims: “Jesus died for me!”
This is the way a righteous and yet merciful God has provided salvation: “For God so loved the world, that he gave his only begotten Son” (John 3:16). Do you see this? It is the heart of the Christian gospel, and the only way to peace with God and the peace of God. This is what a Christian understands and knows.
Trust
“But how do I benefit from what Christ has done for sinners?” you may ask. That, too, is a good question. After all, the provision of something is not the same as the possession of it. We possess God’s free salvation by simply asking for it: committing our guilty souls to Jesus Christ by personal trust. Then, what He did in His life and death becomes ours. We become reconciled to God and enter the Christian life — a real, living relationship with God. “Believe on the Lord Jesus Christ, and thou shalt be saved” (Acts 16:31).
Notice that nothing else is called for but prayerful trust in the Christ of God. This is because He has done all that is necessary to save sinners: His work is finished. To try to add our contribution, in any form, is to insult the free grace of God and put ourselves outside of salvation. Come to Jesus Christ, then, just as you are, confess your sin, ask Him to save you, put yourself entirely in His hands and He will. He will not turn you away; He says, “Him that cometh unto me I will in no wise cast out” (John 6:37).
Obedience
Becoming a Christian means personally knowing Jesus Christ. But it is not a friendship of equals. At conversion, we “receive Christ Jesus the Lord” (Colossians 2:6). That means a real Christian is someone whole lifestyle is under new management. Those whom Jesus saves He also progressively makes holy and prepared for heaven. Christians obey Jesus Christ, He says: “If ye continue in my word, then are ye my disciples indeed” (John 8:31). Obedience to what Jesus says in the Bible is the mark of a Christian. Yet, how many people claim to be Christians and never even read the Bible! Be sure of this — Jesus Christ does not own you as one of His saved ones if your life is not under government of Holy Scripture.