Here Peter confesses that Jesus is the Messiah … the longed for one that the prophets mentioned in the ‘they say’ response in verse fourteen. Christ (Christos) is the Greek equivalent of the Hebrew Messiah. God’s predicted and long-awaited deliverer of Israel.
Peter confesses not that Jesus is merely another in the long line of prophets and teachers proclaiming and longing for the coming Messiah … but that Jesus IS the Christ the supreme ‘Anointed One” … THE Messiah … the long-awaited promised Savior.
Jesus’ response points to the key biblical doctrine of divine revelation. Not just of who Jesus is but of who God reveals himself to be. A key doctrine is revealed here … the doctrine that we cannot know God apart from God giving us the ability to know Him.
Particular/Special Revelation of God is Jesus Christ himself. This is why we are now at the interaction between Jesus and Peter in Matthew 16:16. Peter acknowledges who Jesus is … THE CHRIST … the Messiah who saves … the SON of the living God.
It is impossible for fallen men to see God through reason alone. It is impossible for fallen men to know God through ‘natural revelation’ alone.