A.T. Robertson Commentary Mark 14:62

"And Jesus said, I am: and ye shall see the Son of man sitting at the right hand of Power, and coming with the clouds of heaven." — Mark 14:62 (ASV)

I am (εγο ειμ). Matthew has it, "Thou hast said," which is the equivalent of the affirmative. But Mark's statement is definite beyond controversy. See on Mt 26:64-68 for the claims of Jesus and the conduct of Caiaphas.