Charles Ellicott Commentary Isaiah 1:16

"Wash you, make you clean; put away the evil of your doings from before mine eyes; cease to do evil;" — Isaiah 1:16 (ASV)

Wash you, make you clean...—The words were probably as an echo of Psalm 51:7. Both psalmist and prophet had entered into the inner meaning of the outward ablutions of ritual.

Cease to do evil; (17) learn to do well.—The prophet might have heard such words in his youth from Amos (Amos 5:14–15). What had then been spoken to the princes of the northern kingdom was now repeated to those of Judah.