Jeremiah 18:8

But the Prophet speaks first of punishment; Suddenly, he says, will I speak of a nation and of a kingdom, to pull down, to extirpate and to destroy; that is, even they who seem far from all danger shall find that they are exposed to my judgment. But if a nation, he says, turns from its wickedness, against whom I have spoken, then I will repent of the evil, etc. The Prophet no doubt intended to shut up the mouths of the Jews, who, as we have before seen, continually contended with God; for he could not convince them that the punishments were just which God inflicted on them for their sins. As then they were thus perverse in their wickedness, and hypocrisy also had hardened them the more, the Prophet says here in God’s name, “When I speak against a nation and threaten final ruin, if it repents, I shall be immediately reconciled to it; there is therefore no ground for the Jews to expostulate with me, as though I dealt with them too severely; for they shall find me reconcilable if they repent from the heart.” It follows then, that their obstinacy was the cause why God proceeded in his judgments, for the repentance of God means no other thing than what Scripture says elsewhere, that he is merciful, slow to wrath, and ready to forgive. (Numbers 14:18; Psalms 103:8.) He then here testifies, that nothing hindered the Jews from being in a better state but their own perverseness.