Deuteronomy 7:8-10

Rather, it was simply that the LORD loves you, and he was keeping the oath he had sworn to your ancestors. That is why the LORD rescued you with such a strong hand from your slavery and from the oppressive hand of Pharaoh, king of Egypt. Understand, therefore, that the LORD your God is indeed God. He is the faithful God who keeps his covenant for a thousand generations and lavishes his unfailing love on those who love him and obey his commands. But he does not hesitate to punish and destroy those who reject him.