Three witnesses of the same event hardly ever give exactly the same account of it, but there is usually a sufficient measure of agreement between them to ensure the general veracity of their testimony, even if many of the details remain irreconcilable. This seems to be true of the first three Gospels. The triple tradition at first sight gives reassurance. The differences between them appear to confirm the essential truth of the account, as they suggest that the tradition has been independently attested.

If this is the impression which first strikes the reader of the Synoptic Gospels, more careful study will soon shake his confidence. When the triple tradition is subjected to word-for-word comparison in the Greek, it soon becomes apparent that the similarities are too close to be explained in terms of independent testimony. The Synoptic Gospels are actually interdependent. One evangelist has used the work of another. This means that the differences between them are not due to independent tradition, but are deliberate divergences on the part of the evangelists. And if the two later ones have been so lacking in fidelity to their common source, how can we have any certainty that the original has not been equally unfaithful to the primitive tradition on which it is based ? And if that is so, how can we ever get back to the truth of the matter, and find out what Jesus really did say and do in his life on earth?

This is the essence of the Synoptic Problem, and it has been the central issue before New Testament scholars for the past 150 years.