Deuteronomy 7:9

9 From this you can know that ADONAI your God is indeed God, the faithful God, who keeps his covenant and extends grace to those who love him and observe his mitzvot, to a thousand generations.

Deuteronomy 7:9 Meaning and Commentary

Ver. 9 Know therefore that the Lord thy God, he is God
The only true and living God, and not the idols of the Gentiles, who are false and lifeless ones, and therefore not the proper objects of adoration:

the faithful God, which keepeth covenant and mercy;
as appeared by fulfilling the promise made to their fathers, in bringing them out of Egypt, and now them to the borders of the land of Canaan given them for an inheritance:

with them that love him, and keep his commandments, to a thousand
generations;
see ( Exodus 20:6 ) which are not the causes or conditions of his covenant and mercy, nor of his keeping them, but descriptive of the persons that enjoy the benefit thereof.

Deuteronomy 7:9 In-Context

7 ADONAI didn't set his heart on you or choose you because you numbered more than any other people - on the contrary, you were the fewest of all peoples.

8 Rather, it was because ADONAI loved you, and because he wanted to keep the oath which he had sworn to your ancestors, that ADONAI brought you out with a strong hand and redeemed you from a life of slavery under the hand of Pharaoh king of Egypt.

9 From this you can know that ADONAI your God is indeed God, the faithful God, who keeps his covenant and extends grace to those who love him and observe his mitzvot, to a thousand generations.

10 But he repays those who hate him to their face and destroys them. He will not be slow to deal with someone who hates him; he will repay him to his face.

11 Therefore, you are to keep the mitzvot, laws and rulings which I am giving you today, and obey them.