Mark 8:30

And he charged them that they should tell no man of him.

The charge was given after Peter's confession, at the moment Jesus revealed Himself to the disciples as the Messiah and lifted them from the darkness in which they had been groping. He charged the disciples that they should tell no one that He was the Christ. The command was given because of the determined opposition of the scribes and Pharisees. Still more, it was given because the people and even the disciples had so false a conception of the Messiah that a public announcement would give no true idea of His character or His work. Instead of a public announcement, He was day by day revealing Himself to them as the Saviour, and in that way He desired to give them a true conception of Him as the Messiah.

Immediately after that revelation He told them He must voluntarily go to Jerusalem to live as a humble homeless wanderer and there meet cruel humiliation, to be despised, rejected, and put to death. Beyond the present poverty and humiliation He pointed them to His coming in glory, not with the splendor of an earthly throne but with the glory of God and the hosts of heaven, when He shall reward every man according to his works. For their encouragement He promised that some standing there should not taste of death till they see the Son of man coming in His kingdom. The disciples did not comprehend His words because their eyes were fixed on the nearer view of earthly poverty, humiliation, and suffering and on their glowing expectations of the Messiah exalted to the throne of David. Sadness oppressed their hearts because they loved their Master, and doubt harassed their minds that the Son of God should resign Himself to such a fate and leave them in greater darkness.

The surrounding account concerns His willing sacrifice and the joy set before Him.