Joe Wallack over at FRDB argues that Jesus’ prediction “ahead of you in Galilee” Mark 14:28 and the young man’s reiteration in 16:7 were interpolations. It is possible.
The gospel of Peter uses Mark’s tomb appearance but leaves out the prediction:
He is risen and gone away. But if you do not believe, bend down and see the place where he lay, because he is not here. For he is risen and gone away to there whence he was sent.’ Then the women fled frightened.
The use of women being solely frightened is only found in Mark; Luke and Matthew have them being frightened and overjoyed at the same time. Also, Mark is the only one that describes the person at the tomb in the pedestrian term “youth” or “young man”. Luke/Matthew have more “bombastic”, supernatural messengers who announce that Jesus has risen. Both of these evidence that Peter is more faithful to Mark than the other synoptics. Since Peter doesn’t have the Galilee prediction, the original version of Mark might not have had it either.
If Mark 14:28 is taken out of the context, it still makes sense:
“You will all fall away,” Jesus told them, “for it is written:” ‘I will strike the shepherd, and the sheep will be scattered.'”
29Peter declared, “Even if all fall away, I will not.”
30″I tell you the truth,” Jesus answered, “today—yes, tonight—before the rooster crows twice you yourself will disown me three times.”
31But Peter insisted emphatically, “Even if I have to die with you, I will never disown you.” And all the others said the same.
It reads a lot smoother than it does with Jesus’ prediction of going ahead of them in Galilee. Jesus also quotes Zechariah 13:7. This might be more of that overzealous prophecy fulfillment that I wrote about in an earlier post that also might not be original to Mark. Though I admit that’s a stretch 😉