Deuteronomy 7:9-11

9Know therefore that the LORD thy God, he is God, the faithful God, who keepeth covenant and mercy with them that love him and keep his commandments to a thousand generations; 10And repayeth them that hate him to their face, to destroy them: he will not be slack to him that hateth him, he will repay him to his face. 11Thou shalt therefore keep the commandments, and the statutes, and the judgments, which I command thee this day, to do them.