Adam Clarke on Isaiah 44:22

I have blotted out, as a thick cloud, thy transgressions, and, as a cloud, thy sins "I have made thy transgressions vanish away like a cloud, and thy sins like a vapor" - Longinus admired the sublimity of the sentiment, as well as the harmony of the numbers, in the following sentence of Demosthenes: Τουτο το ψηφισμα τον τοτε τῃ πολει τερισταντα κινδυνον παρελθειν εποιησεν ὡσπερ νεφος. "This decree made the danger then hanging over the city pass away like a cloud." Probably Isaiah alludes here to the smoke rising up from the sin-offering, dispersed speedily by the wind. and rendered invisible. He who offered his sacriflce aright was as sure that the sin for which he offered it was blotted out, as that the smoke of the sacrifice was dispersed by the wind, and was no longer discernible.