Charles Spurgeon Commentary Jonah 3:10

"And God saw their works, that they turned from their evil way; and God repented of the evil which he said he would do unto them; and he did it not." — Jonah 3:10 (ASV)

There is no change in God, absolutely considered, but there is often an apparent change: what he threatens while people remain in sin is not executed upon them when they repent and turn to him.

He is always the same God. From the beginning, he has been the Lord God, merciful and gracious, long-suffering, and abundant in goodness and truth, keeping mercy for thousands, forgiving iniquity and transgression and sin. If he did not pardon sin when people turn from it with sincere repentance, he would have changed his method of dealing with the penitent; but when he does forgive, it is according to his way from the beginning, for he has ever been a tender, and compassionate, and gracious God.