Isaiah 43:25

"I, even I, am he that blotteth out thy transgressions for mine own sake; and I will not remember thy sins. Put me in remembrance; let us plead together: set thou forth thy cause, that thou mayest be justified. Thy first father sinned, and thy teachers have transgressed against me. Therefore, I will profane the princes of the sanctuary; and I will make Jacob a curse, and Israel a reviling."

Isaiah 43:25 does not mean that God is forgiving Israel's sins without regard to their penitence; but it calls attention to the truth that only God can forgive their sins. The mention of the sins of "their first father," evidently Jacob, is apparently brought in here to demonstrate that the whole history of the Jews has been a dreary account of their wickedness and rebellion against God. Will God actually overlook all this and forgive the fleshly descendants of Abraham no matter what they do? Who could believe such a thing?

Adam Clarke commented on this final verse thus:

"Alas! What a curse does the old Israel still bear, and what reproach do they still suffer? No national crimes have ever equaled those of the Jewish nation; for no nation ever had such privileges to neglect, despise, and sin against. When shall the severity of God toward this people have an end? Answer: Whenever, with one heart, they turn to him, and receive the doctrine of the Lord Jesus Christ; and not till then."[18]