This Bible contradiction is from the Skeptic's Annotated Bible.
Matthew 26:36-42 View context
Then cometh Jesus with them unto a place called Gethsemane, and saith unto the disciples, Sit ye here, while I go and pray yonder.
And he took with him Peter and the two sons of Zebedee, and began to be sorrowful and very heavy.
Then saith he unto them, My soul is exceeding sorrowful, even unto death: tarry ye here, and watch with me.
And he went a little further, and fell on his face, and prayed, saying, O my Father, if it be possible, let this cup pass from me: nevertheless not as I will, but as thou [wilt].
And he cometh unto the disciples, and findeth them asleep, and saith unto Peter, What, could ye not watch with me one hour?
Watch and pray, that ye enter not into temptation: the spirit indeed [is] willing, but the flesh [is] weak.
He went away again the second time, and prayed, saying, O my Father, if this cup may not pass away from me, except I drink it, thy will be done.
Mark 14:35-36 View context
And he went forward a little, and fell on the ground, and prayed that, if it were possible, the hour might pass from him.
And he said, Abba, Father, all things [are] possible unto thee; take away this cup from me: nevertheless not what I will, but what thou wilt.
Luke 22:41-42 View context
And he was withdrawn from them about a stone's cast, and kneeled down, and prayed,
Saying, Father, if thou be willing, remove this cup from me: nevertheless not my will, but thine, be done.
John 12:27 View context
Now is my soul troubled; and what shall I say? Father, save me from this hour: but for this cause came I unto this hour.