Matthew 16:15-17, 20

He said to them, “But who do you say that I am?” Simon Peter answered and said, “You are the Christ, the Son of the living God.” Jesus answered and said to him, “Blessed are you, Simon Bar-Jonah, for flesh and blood has not revealed this to you, but My Father who is in heaven.

Then He commanded His disciples that they should tell no one that He was Jesus the Christ.