I, even I - the God against whom your sin is committed, and who alone can and will pardon. (Isa 44:22).
for mine own sake - (Isa 48:9, Isa 48:11). How abominable a thing sin is, since it is against such a God of grace! “Blotted out” is an image from an account-book, in which, when a debt is paid, the charge is cancelled or blotted out.
not remember ... sins - (Jer 31:34). When God forgives, He forgets; that is, treats the sinner as if He had forgotten his sins.