The answer to this question can, I think, be given in one sentence, even though the one-sentence answer could be unfolded at great length. 'Christianity is too incredible not to be true!' By this I do not mean that it is the tallest of tall stories, the most extraordinary example of how much Jones will swallow. What I do mean is that myth-makers never invent stories like it. Consider the facts:

1. You do not invent a story about an engaged woman conceiving a child and claiming that no man was involved. Scripture assures us that Mary was a virgin before conception and a virgin until after Jesus was born. You do not invent such a story if you want the Gospel to gain easy acceptance among Jews, for they held pre-marital chastity in such high regard that a woman could be stoned to death if proved to have been unchaste before marriage.
   
   The Virgin Birth is so clearly a black mark against Mary and Joseph — and our Lord Himself — that the really incredible thing is to believe that the Early Church invented the idea! Nor do you invent such a story if you want the Gospel message to carry conviction in the Gentile world among non-Jews.
   
   To speak generally, the Gentiles were at the opposite end of the spectrum to the Jews. Among them chastity was held in little regard. So a story of a virgin who conceived without sexual relations would simply invite ribald jokes! Such a story has got to be true or there is no point in it whatsoever.
    
2. A person does not make the claim to be the Son of God, as Jesus did, if he is not speaking the truth. It would be utterly absurd to make such a claim, in the context in which it was made, if it were not true. Because the Jews were strict monotheists (Deuteronomy 6:4), any man — and Jesus was clearly that — who claimed to be the Son of God must, in their view, be either mad or a blasphemer. There is no evidence that the Jews regarded our Lord as mad, but every evidence that their real charge against Him was that He was a blasphemer. Their trumped-up charge that He was an insurrectionist was to get Him executed by the Romans. The real charge was that He was a blasphemer (John 10:30-33). Again, I say, no man invents a story like this. Nothing was more calculated to be rejected outright by all Jews than the claim of Jesus to be the Son of God. Yet He gave no appearance of being deluded. Quite the opposite, in fact, for He deliberately concealed His deity and Messiahship from the people generally and only gradually revealed His secret to His disciples. Deluded people do not keep such secrets to themselves! Nor was anyone able to convict our Lord of lying. There is no evidence to suggest that any of His opponents tried to prove that He was lying. So if He was not deluded, and if He was not a liar, we are left with the only — and, to unbelievers, the incredible alternative — that He was, in very truth, the Person He claimed to be — the Son of God incarnate. Should some be inclined to argue (as certain scholars are) that the deity of Christ is a dogma invented by the early Church as it prosecuted its mission in the Gentile world, we can produce undeniable facts.
   
   That the gods of Greek mythology were regarded as having sons is undeniable, but what is equally certain is that any emphasis upon the unique Sonship of Jesus would have been quite unacceptable to the Greek mind. 'The only begotten of the Father' (John 1:14) was not a name of Jesus likely to have found acceptance among polytheistic and syncretistic thinkers. Yet it is precisely in the Gospel which is alleged to have the strongest links with Greek philosophy, the Gospel of John, that the deity, exclusiveness of mission, and finality of Jesus are most strongly asserted, when one might have expected the opposite to be the case.
   
   So Thomas confesses:

 My Lord and my God.                                                  John 20:28

The prologue declares:

No man hath seen God at any time: the only begotten Son, who is in the bosom of the Father, he hath declared him.John 1:18

The Lord Himself is recorded as saying:

I am the way, the truth, and the life; no man cometh unto the Father, but by me.John 14:6

We are quite unable to suppose that the early Christian missionaries should have burdened themselves with a message which they knew would arouse scorn in the Gentile world, if they were not fully persuaded of the truth that the son of Mary was the Son of God. And we are equally unable to suppose that those who were with Jesus for three years — Jewish monotheists to a man — should have turned a mere man into the Son of God, and foisted this idea upon others, knowing (on the modernist argument) it not to be true.

Again I say that the incarnation of the Son of God — deity made known in true humanity — is incredible, too incredible not to be true, and all reasons put forward to explain it as mere myth and fancy fade away into oblivion. If our Lord was not the Person He claimed to be — the eternal Son of the eternal Father — He is not worthy of our belief. Either He was deluded or He was not even a good man, but a deceiver.

3. The resurrection of Christ is yet another fact too incredible not to be true. The empty tomb resists all attempts to explain it away. If the disciples had themselves taken away the body of our Lord, Christianity would have been still-born, for all the evidence makes it clear that they had to be persuaded against their own personal judgement that Jesus would and did rise from the dead. If the enemies of Christ had His body all they had to do was to produce it in order to demolish the claim that He had risen from the dead. Had anyone else stolen the body, a robber of graves, for example, is it likely that he would not have given it the Jewish authorities to enable them — for a suitable reward! — to scotch the rumour that swept Jerusalem so soon after the death of Jesus that He had risen from the dead? To suppose, as some have done, that our Lord never actually died on the cross, but swooned so as to appear to be dead, involves a veritable miracle of unbelief. As Clark Pinnock aptly comments:

This theory is harder to believe than the biblical account. It is past belief how Jesus could have survived a crucifixion of six hours and a Roman spear wound, and convinced Pilate and his executioners that he was dead. Then in a state of terrible physical pain he endured the coldness of the tomb for three days, removed the large boulder at the door of the grave, eluded the guard posted at the sepulchre, convinced his disciples that he had a glorious resurrection, and finally disappeared and died in anonymity.Set Forth Your Case, pp 65-66

That the resurrection of Christ was central in the apostolic preaching from the day of Pentecost onwards, no one can deny. The only reasonable explanation is that it was central because it happened — and it happened precisely as Jesus foretold. Now who would hang everything on the resurrection, as Paul does in 1 Corinthians 15:17, if at best it was problematic and at worst a down-right lie? And why put yourself out on a limb, as he did — claiming only some twenty years after the event, that most of the witnesses indeed, the more than 500 who saw him simul­taneously were still alive (15:6) — if the resurrection did not happen! Who takes more believing — the apostle or the bishop of Durham?

4. Last of all, the grace of God in the Gospel is too incredible not to be true. Does proud, self-centred man invent a message which declares that a man cannot contribute one iota to his own salvation (Ephesians 2:8)? Does he concoct a story about a cross which leaves him with no ground to boast? Does he fabricate a gospel which declares the best of men utterly unfit for the presence of the all-holy God? There is no other religion known among men which dethrones man and exalts God as Christianity does. The Gospel of Christ sets at nought the wisdom of man (1 Corinthians 1:22-24). This in itself is a most powerful testimony to its truth and divinity, as all who have been granted spiritual sight readily see.
   
   The grace of God in the Gospel has about it the incredibility of truth — truth which lays hold of the heart and captivates the mind and sets our brief lives in the context of eternity — for 'the chief end of man is to glorify God and enjoy Him forever!'

Is Christianity true? Yes! For it is so self-consistently incredible and so glorifying to God as to render it an impossibility for anyone to have invented it.