Albert Barnes Commentary Psalms 51:9

"Hide thy face from my sins, And blot out all mine iniquities." — Psalms 51:9 (ASV)

Hide thy face from my sins - That is, do not look on them; avert your face from them; do not regard them. Compare the notes at Psalm 13:1.

And blot out all mine iniquities - Take them entirely away. Let the account be erased, cancelled, destroyed. See the notes at Psalm 51:1.