Deuteronomy 7:9-12

Know therefore that the LORD your God is God; he is the faithful God, keeping his covenant of love to a thousand generations of those who love him and keep his commandments. But those who hate him he will repay to their face by destruction; he will not be slow to repay to their face those who hate him. Therefore, take care to follow the commands, decrees and laws I give you today. If you pay attention to these laws and are careful to follow them, then the LORD your God will keep his covenant of love with you, as he swore to your ancestors.