Was there any contradiction between God’s change of heart and His wrath? Of course not! This is because God’s tolerance at that particular time had its reason. What reason might this be? It is the one given in the Bible: “Every person turned away from his evil way” and “abandoned the violence in their hands.”
This “evil way” does not refer to a handful of evil acts, but to the evil source behind people’s behavior. “Turning away from his evil way” means that those in question will never commit these actions again. In other words, they will never behave in this evil way again; the method, source, purpose, intent and principle of their actions have all changed; they will never again use those methods and principles to bring enjoyment and happiness to their hearts. The “abandon” in “abandon the violence in their hands” means to lay down or to cast aside, to fully break with the past and to never turn back. When the people of Nineveh abandoned the violence in their hands, this proved as well as represented their true repentance. God observes people’s exteriors as well as their hearts. When God observed the true repentance in the hearts of the Ninevites without question and also observed that they had left their evil ways and abandoned the violence in their hands, He changed His heart. This is to say that these people’s conduct and behavior and various ways of doing things, as well as the true confession and repentance of sins in their heart, caused God to change His heart, to change His intentions, to retract His decision and not to punish or destroy them. Thus, the people of Nineveh achieved a different end. They redeemed their own lives and at the same time won God’s mercy and tolerance, at which point God also retracted His wrath.
from God Himself, the Unique II