I have seen thine adulteries - Thy idolatries of different kinds, practiced in various ways; no doubt often accompanied with gross debauchery.
Wo unto thee, O Jerusalem wilt thou not be made clean? - We see from this, that though the thing was difficult, yet it was not impossible, for these Ethiopians to change their skin, for these leopards to change their spots. It was only their obstinate refusal of the grace of God that rendered it impossible. Man cannot change himself; but he may pray to God to do it, and come to him through Christ, that he may do it. To enable him to pray and believe, the power is still at hand. If he will not use it, he must perish.
And thine abominations - “Even thy abominations.” The prophet sums up the three charges against Judah, namely, spiritual adultery, inordinate eagerness after idolatry (see the note at Jeremiah 5:7 note), and shameless participation in pagan orgies.
Wilt thou not once be? - “Or, how long yet ere thou be made clean!” These words explain the teaching of Jeremiah 13:23. Repentance was not an actual, but a moral impossibility, and after a long time Judah was to be cleansed. It was to return from exile penitent and forgiven.