Ambrose of Milan — as excerpted in the Catena Aurea on Luke 22:54-62

“Peter denied, because he promised rashly. He does not deny on the mount, nor in the temple, nor in his own house, but in the judgment-hall of the Jews. There he denies where Jesus was bound, where truth is not. And denying Him he says, I know him not. It were presumptuous to say that he knew Him whom the human mind can not grasp. For no one knoweth the Son but the Father. (Matt. 11:17). Again, a second time he denies Christ; for it follows, And after a little while another saw him, and said, Thou wert also one of them.”