Deuteronomy 7:10 KJV
And 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.
Deuteronomy 7:10, King James Version
In context
9 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;
10 And 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.
11 Thou shalt therefore keep the commandments, and the statutes, and the judgments, which I command thee this day, to do them.