Mark 8:31

And he began to teach them, that the Son of man must suffer many things, and be rejected of the elders, and of the chief priests, and scribes, and be killed, and after three days rise again.

At Caesarea Philippi Jesus began to prepare His disciples for His betrayal, trial, and crucifixion by teaching that He must suffer many things, and be rejected by the elders and chief priests and scribes, and be killed, and after three days rise again. He said He would voluntarily go to Jerusalem as a humble, homeless wanderer to meet rejection and death there. There He would be despised, delivered into His enemies' hands, and put to death in cruel humiliation on the cross at Calvary, and would rise the third day. The teaching was given plainly and carefully before the crucifixion, while Satan was laying his plans against Him, when the disciples did not yet know how near these events were and that He would soon leave them without His visible presence.

Jesus knew beforehand the suffering, rejection, and death awaiting Him, with the whole path from the manger to Calvary lying before Him before He took humanity, and He willingly accepted every anguish, insult, and privation. The suffering, rejection, death, and resurrection after three days were necessary parts of His mission. By His death He would bear the world's sins and give His life for humanity, delighting to do God's will to save the lost. Though the coming suffering was immense He endured it for the joy of winning the world back to loyalty to God. His suffering and death on the cross were necessary rather than worldly honor and a throne.

The disciples could not accept this because their eyes were fixed on earthly expectations: deliverance from Roman rule and the Roman yoke, worldly honor and a throne, the Messiah reigning as a powerful king and exalted to the throne of David. They loved Him yet were oppressed with sadness and harassed with doubt, finding it incomprehensible that the Son of God should be subjected to poverty, humiliation, and suffering while His glory seemed far away. They questioned why He would resign Himself to such a fate and leave them in greater darkness than before. Peter rejected the teaching because he thought such an event would ruin the church and that the Lord should prevent it.

Though angels were present to impress His words on minds and hearts, the disciples were dull in understanding and could not comprehend what He told them. The words they needed to remember were forgotten and banished from their minds because they could not tolerate the thought that He in whom all their hopes centered should suffer an ignominious death. So when the time of trial came it found them unprepared and His death destroyed their hopes as fully as if He had not forewarned them. Peter's response turned the disciples away from the lesson Jesus wanted to teach them.

The verse teaches that His mission would bring shame and suffering rather than worldly honor, and that following Him would bring suffering, reproach, and shame. His followers must give up hope in the world's honor and pleasures, be willing to endure reproach for His sake to win salvation, and share His glory only after enduring hardship with Him. In this way He prepared them for the trials and persecution they would face. The verse proves the future can be opened as plainly as Christ opened it to the disciples yet remain ununderstood. It warns that the events connected with the close of probation and the work of preparation for the time of trouble are clearly presented in prophecy, but multitudes have no more understanding of them than if they had never been revealed, because Satan watches to catch away every impression that would make them wise unto salvation, leaving them unready when the time of trouble comes.