Luke 22:31

Simon, Simon, behold, Satan asked to have you, that he might sift you as wheat: but I made supplication for thee, that thy faith fail not; and do thou, when thou hast turned again, establish thy brethren. And he said unto him, Lord, with thee I am ready to go both to prison and to death. And he said, I tell thee, Peter, the cock shall not crow this day, until thou shalt thrice deny that thou knowest me.

The episode of Peter's denial was fully treated in my Commentary on Matthew, Matthew 26:31-35 and Matthew 26:69-75, and likewise in the parallels in Mark 14:30ff and in John 13:36-38; John 18:15-27.

Satan asked to have you ... Christ here spoke of the kingdom of evil as a domain ruled over by an intelligent, personal head. Peter's defection was not due so much to his personal weakness as it was to the weakness of all men without the Saviour. The Great Sacrifice had not yet been offered. For a few hours, the Prince of Life would be under the dominion of the powers of darkness; and it was impossible that under those conditions Peter could make good his boast. Besides, his heart, even then was not completely in tune with the will of God.

Geldenhuys observed that "The inclusion of this prediction and its subsequent fulfillment is a testimony to the historical truth"[18] of the gospels. It is impossible to believe that the primitive church would have invented, or circulated, such a story, about such an apostle as Peter, if, in fact, it had been anything other than historical truth.

THE CHANGED STATUS OF THE APOSTLES

Upon the eve of his death, the Lord called attention to a dramatic change in the status of the apostles. Until that time, there had been no need for them to be concerned in any manner with worldly needs and provisions, the Lord having taken care of everything; but, with his death, resurrection, and ascension to the other world, all that was to be changed. Prudence, foresight, even means for self-defense, would be needed: and so he instructed them.