133. But forasmuch as then the Seraph came down in a vision to the Prophet, whilst Thou, O Lord, in revelation of the mystery hast come to us in the flesh, St. Ambrose contrasts the appearance of the Seraph to Isaiah in a vision with our Lord’s appearance to men in everyday life, in the flesh, see Is. vi. 6, 7, and 1 Tim. iii. 16. do Thou, not by any deputy, nor by any messenger, but Thou Thyself cleanse my conscience from my secret sins, that I too, erstwhile unclean, but now by Thy mercy made clean through faith, may sing in the words of David: “I will make music to Thee upon a harp, O God of Israel, my lips shall rejoice, in all my song to Thee, and so, too, shall my soul, whom Thou hast redeemed.” Ps. lxxi. 22, 23.