“But what about you?” [Jesus] asked. “Who do you say I am?” (Matthew 16: 15).
"Simon Peter answered, “You are the Messiah, the Son of the living God.” (Matthew 16: 16).
Abba Father revealed to Peter the identity of His Son Jesus the Christ.
What is a revelation? A revelation is the spontaneous flash of truth in the mind. Some examples:
"I keep asking that the God of our Lord Jesus Christ, the glorious Father, may give you the Spirit of wisdom and revelation, so that you may know him better." (Ephesians 1: 17).
"When I saw that man/woman, I knew immediately that was he/she."
We all enjoy revelation from time to time.
And Jesus said to Peter: "You are Peter, and upon this rock I will build my church, and the gates of the netherworld shall not prevail against it." (Matthew 16: 18).
God gives us knowledge of Himself and His works that we may come to know Him, love Him and serve Him so that we can enjoy eternity with Him forever.