Matthew 16:20

Then charged he his disciples that they should tell no man that he was Jesus the Christ.

The charge was given after Peter confessed Jesus as the Christ. Jesus charged His disciples to tell no man publicly that He was Jesus the Christ. He gave this charge because the scribes and Pharisees were determinedly and firmly opposed to Him.

The people and even the disciples themselves misunderstood the Messiah's character and work, so a public announcement would not have given them a true understanding of Him. Instead He wanted recognition to come through daily experience of Him and through the evidence of His words and works, revealing Himself to the disciples day by day so they would come to know Him truly as Messiah and Saviour. The silence was only for a time, for near the close of His earthly ministry He intended His identity and mission to be made unmistakable through the public fulfillment of prophecy during His final journey toward Jerusalem, leaving no student of Scripture in doubt.