I suggest that what Jesus actually said meant or implied something like this “Before the cock crows tomorrow morning, and before he crows twice, you will deny me three times”. He was thus making a lesser and included prediction that the cock would crow once before the coming of Good Friday morning.

Each of the Gospels accurately record part of what Jesus predicted. None record all of what he predicted. As usual, the fullest picture is achieved by reading all of the accounts.

Mark’s account, which is thought to be Peter’s account, recalls the prediction of both crowings because Peter lived through the crowings and the denials first hand. That is what was most vividly memorable to Peter. It was that second crowing that brought Jesus’ words back to his mind.

The single-crower accounts are mostly just concerned with recording the part of the prediction that implied that the denials would happen before Good Friday morning.

Well, as I said, I believe the strongest inconsistency requires you to look at both at once (especially Mark 14:68 vs. Luke 22:34).

Still, putting that aside for now, I agree that the predictions recorded by Mark and Matthew are not entirely consistent. I’m sure you’re right that “before the cock crows twice” implies that it will crow once (as indeed Mark later says it does).

I do think that the predictions are worth examining on their own. There are two angles on this that I can see.

First, Mark and Matthew are clearly recording the same conversation (in Luke and John the conversations are rather different). There’s a significant difference in meaning between “before the cock crows” (Matthew) and “before the cock crows twice” (Mark), so which did Jesus actually say in that conversation?

Note that this isn’t about the predictions contradicting each other, but about the reports of Jesus making the prediction contradicting each other. I do, however, think that there’s a second way to approach this that does take the predictions to be contradictory.

I assume that you say that the predictions don’t contradict each other very strongly because “before the cock crows twice” and “before the cock crows” are mutually consistent; anything that satisfies the latter also satisfies the former. However, I think that a case can be made that “before the cock crows twice” implies “after the cock crows once”, in which case the two predictions would be inconsistent.

They’re the two ways in which I think the accounts of the predictions are problematic; any comments?

If you really want to establish a contradiction, then I suggest the problem is actually caused by Mark 14:68.

i.e. Mark tells us that Peter denied Jesus once, and the cock crew, whereas all the other gospels (especially Luke, who says it in the strongest way) tell us that Jesus predicted the cock would not crow at all until Peter had denied him three times…