Why must one be a Christian?

The question carries real weight, and it deserves better than a slogan. Why should anyone need to be a Christian specifically? Why is sincerity not enough? Is it not simply narrow to insist on one road?

The Christian answer is not that Christians are better, or that other people are stupid. It is that there is one problem every human being has, and one place it has been dealt with.

The problem is universal, and it is not behaviour management

Scripture's diagnosis is that every person is estranged from God, and that this is a condition rather than a scorecard. "All have sinned and fall short of the glory of God" (Romans 3:23). The standard is not other people; it is God himself.

The consequence is stated just as plainly: "the wages of sin is death" (Romans 6:23). Not only biological death but separation from the source of life. And it is not indefinitely deferrable: "it is appointed for man to die once, and after that comes judgement" (Hebrews 9:27).

If that diagnosis is wrong, Christianity is unnecessary. If it is right, then any religion that offers you a self-improvement programme is offering physiotherapy to a corpse.

Why effort cannot solve it

Every other religious system, at its base, asks you to do something: keep the law, follow the path, accumulate merit, perform the duty. The reward is proportional to the performance.

Christianity says the debt is not the kind of thing that can be worked off. If you owed a fortune and paid a hundred a month, you would still be in debt — and meanwhile you keep spending. Worse, the currency is wrong: the offence is against an infinite God, and finite good behaviour is not the right kind of thing to settle it.

God justifies the ungodly. There is no other way for God to justify us, since we are all ungodly.— Charles Spurgeon, All of Grace

This is the point at which the gospel becomes genuinely different rather than merely different in detail. It does not offer better terms on the debt. It says the debt has already been paid by someone else, and the only question is whether you will accept the receipt.

Why Jesus specifically

Four things distinguish him from every other founder of a world religion, and all four have to be taken together:

1. He claimed to be God, not merely to speak for God. Moses, Muhammad, the Buddha and every Hebrew prophet pointed away from themselves. Jesus said "before Abraham was, I am" (John 8:58) — using the divine name of Exodus 3:14 — and his hearers immediately picked up stones, because they understood exactly what he had said.
2. He claimed his death was a purposeful substitution. "The Son of Man came not to be served but to serve, and to give his life as a ransom for many" (Mark 10:45). Not a martyrdom that went wrong. A transaction that was the point.
3. He was reported risen by named witnesses who had nothing to gain. Over five hundred at once, most still alive when Paul wrote it down and invited readers to go and ask them (1 Corinthians 15:6).
4. Those witnesses died rather than retract. People die for false beliefs constantly. People do not generally die for what they personally know to be a lie about something they claim to have seen with their own eyes.

That combination exists nowhere else. Which is why Peter, standing in front of the council that had just executed his teacher, said: "there is salvation in no one else, for there is no other name under heaven given among men by which we must be saved" (Acts 4:12).

Exclusivity is unavoidable, not arrogant

The mutually exclusive claims are not incidental. The Quran states that Jesus was not crucified (Surah 4:157); the New Testament and every relevant non-Christian historical source say he was. One of these is false. Refusing to notice is not tolerance; it is a decision not to take anyone seriously.

Real tolerance means: I think you are wrong about something enormous, I will represent your view accurately, I will defend your right to hold it, and I will treat you as fully my equal while we disagree. That is a far more demanding posture than pretending the disagreement is not there.

What is actually at stake

"Whoever believes in the Son has eternal life; whoever does not obey the Son shall not see life, but the wrath of God remains on him" (John 3:36).

Read that last clause carefully. It says remains — not "descends". The picture is not of a neutral person on whom judgement suddenly falls, but of someone already in a condition, standing in an open doorway, choosing not to walk through it. Hell in the New Testament is never a surprise; it is the ratification of a direction already travelled. As Lewis put it, in the end there are only two kinds of people: those who say to God "your will be done", and those to whom God says, finally, "your will be done".

And therefore how to hold it

If this is true, two things follow at once, and holding only one of them is a failure.

The first is urgency. Paul said "necessity is laid upon me. Woe to me if I do not preach the gospel" (1 Corinthians 9:16). If a house is burning you do not wait for a convenient moment.

The second is gentleness. "Always be prepared to make a defence to anyone who asks you for a reason for the hope that is in you; yet do it with gentleness and respect" (1 Peter 3:15). The word Peter uses for defence is apologia — a courtroom word. Make the case. Do not make war.

A Christian who has the urgency without the gentleness will win arguments and lose people. A Christian who has the gentleness without the urgency will be very pleasant company and will never actually tell anyone anything. The gospel requires both, from the same person, in the same conversation.