The Mystery of The Kingdom of God~
Mystery designates the secret plans, thoughts, and dispensations of God that are hidden from human reason, as well as from all other comprehensions below the divine level, and hence must be revealed to those for whom they were intended. However, the mystery is proclaimed to all even though only those who believe understand it. All are summoned to faith; but only those who respond are shown to have spiritual perception and understanding (i.e. only to those who have been "given the mystery" as Mark 4:11 says.) The same can be said of Peter in Matthew 16. Jesus asks him, "But who do you say that I am?" Simon Peter answered, "You are the Christ, the Son of the living God." And Jesus said to him, "Blessed are you, Simon Barjona, because flesh and blood did not reveal this to you, but My Father who is in heaven." Jesus is clearly indicating that one must receive supernatural illumination to understand the truth that Jesus is the Son of God. Although the mystery is proclaimed and is in plain sight to all, not all are "given" this understanding. "Flesh and blood" is morally incapable of revealing it.