What does Matthew 16:21 mean?
With this verse, a shift begins in Jesus' life and ministry, a change that will baffle His followers. To this point, Jesus has kept mainly to the region of Galilee in northern Israel, in addition to travelling to some Gentile regions around Galilee. He has avoided spending much time in Jerusalem, the religious and political heart of Israel. In fact, when He did come into conflict with Jewish religious leaders, He often left the area to keep things from escalating (Matthew 15:21).Now, though, Jesus begins to show the disciples that time has ended. Instead, shockingly, Jesus begins to tell them that He must go to Jerusalem. He says to them clearly that He will suffer at the hands of the elders, chief priests, and scribes. In fact, He will be killed and then raised on the third day.
We know from the rest of the story that Jesus' mission was to die as a perfect, sinless sacrifice for the sins of humanity (John 12:32–34). This verse reveals that Jesus knew it also. He understood what must happen to Him for salvation to come, and He would not resist it (John 12:23–28). In their limited knowledge, Peter and the other disciples would resist that idea.