Thou hast said - This is a form of assenting or affirming. Thou hast said the truth; or, as Luke Luke 22:70 has it, “Ye say that I am.” This was not, however, said “immediately.” Before Jesus acknowledged himself to be the Messiah, he said to them Luke 22:67-68, “If I tell you ye will not believe, and if I also ask you” - that is, propose the proofs of my mission, and require you to give your opinion of them “ye will not answer me, nor let me go.”
Nevertheless - This word should have been translated: “moreover or furthermore.” What follows is designed to explain and give confirmation to what he had said.
Sitting on the right hand of power - That is, of God, called here the Power - equivalent to “the Mighty, or the Almighty.” It denotes dignity and majesty; for to sit at the right hand of a prince was the chief place of honor. See the notes at Matthew 20:21.
Coming in the clouds of heaven - See the notes at Matthew 24; Matthew 25. The meaning of this is, You shall see “the sign from heaven” which you have so often demanded; even the Messiah returning himself “as the sign,” with great glory, to destroy your city and to judge the world.