Deuteronomy 7:9 in the King James Version
Know therefore that the LORD thy God, he is God, the faithful God, which keepeth covenant and mercy with them that love him and keep his commandments to a thousand generations;
Context
8 but because the LORD loves you, and because he desires to keep the oath which he swore to your fathers, the LORD has brought you out with a mighty hand and redeemed you out of the house of bondage, from the hand of Pharaoh king of Egypt.
9 Know therefore that the LORD your God himself is God, the faithful God, who keeps covenant and loving kindness to a thousand generations with those who love him and keep his commandments,
10 and repays those who hate him to their face, to destroy them. He will not be slack to him who hates him. He will repay him to his face.