Jamieson, Fausset and Brown on Isaiah 44:22

22. blotted out--the debt of thy sin from the account-book in which it was entered (Ex 32:32, 33; Re 20:12).

as a thick cloud--scattered away by the wind (Psa 103:12).

as a cloud--a descending gradation. Not only the "thick cloud" of the heavier "transgressions," but the "cloud" ("vapor" [Lowth], not so dense, but covering the sky as a mist) of the countless "sins." These latter, though not thought much of by man, need, as much as the former, to be cleared away by the Sun of righteousness; else they will be a mist separating us from heaven (Psa 19:12, 13; 1Jo 1:7-9).

return ... for--The antecedent redemption is the ground of, and motive to, repentance. We do not repent in order that He may redeem us, but because He hath redeemed us (Zec 12:10; Lu 24:47; Ac 3:18,19). He who believes in his being forgiven cannot but love (Lu 7:43, 47).