What does God do when Israel or mankind deserves to be destroyed?

Les teaches that if God reacted according to what was fair, without grace and mercy, He would have wiped the human race out and wiped Israel out time and again. He uses Israel’s golden calf incident as an illustration: while Moses was up in the mountain, Israel danced in lewdness and immorality, and God could have destroyed them with one thought. Yet God told Moses later in Deuteronomy 33, “I will have compassion on whom I will have compassion, I will have mercy on whom I will have mercy,” because He is sovereign and can do whatever He wants. So when Israel or mankind reaches the point where He should have zapped them and had them off the scene, He retreated into His sovereignty, and by grace He poured out mercy. Les explains that God did the same with Saul of Tarsus. He could have zapped him on the road to Damascus, but instead He retreated into sovereignty, said He would have compassion on that man because He is God, and spared and saved him by His grace. Saul succumbed immediately to the grace of God and responded, “Who art thou Lord?” God also told Ananias that He would send this man far hence to the Gentiles, and he would suffer for His name’s sake.