John Gill Bible Commentary

Hide thy face from my sins,.... In whose sight they were committed, being now ashamed of them himself, and ashamed that any should see them, and especially his God; and being filthy and nauseous, he knew they must be abominable to him, who is of purer eyes than to behold iniquity; and being breaches of his law, must be offensive to him, and provoke the eyes of his glory; and were such that he knew would not bear the examination of justice; and that if God was strict to mark them, he could not stand before him: moreover, in this petition the psalmist deprecates a severe chastisement of them, which is sometimes expressed by setting sins before him, Psa 90:8; and entreats the pardon of them, or oblivion and non-remembrance of them, that they might be cast behind his back, and into the depths of the sea; and blot out all mine iniquities; as in Psa 51:1; here repeated, to show his deep sense of them, and his great importunity for the forgiveness of them; and adds the word all, including all his other sins, with those he had lately committed; for he knew that, if anyone, was left unpardoned, he could never answer for it.