John Calvin Commentary Deuteronomy 7:9

"Know therefore that Jehovah thy God, he is God, the faithful God, who keepeth covenant and lovingkindness with them that love him and keep his commandments to a thousand generations," — Deuteronomy 7:9 (ASV)

Know therefore that the Lord your God, he is God. The verb²²⁰ might have been just as properly translated in the future tense. If this is preferred, an experimental knowledge, as it is called, is referred to, as if he had said that God would practically manifest how faithful a rewarder He is of His servants. But if the other reading is preferred, Moses exhorts the people to be assured that God sits in heaven as the Judge of men, so that they may be both alarmed by the fear of His vengeance and also attracted by the hope of reward.

This declaration, however,²²¹ was appended to the Second Commandment and there explained. Since it is comprehended in the Decalogue, it was not right to separate it from there. But since it is now repeated in confirmation of the whole Law, it is fittingly inserted in this place. It will not be out of place, nevertheless, slightly to touch upon what I there more fully explained.

The promise stands first, because God chooses rather to invite His people by kindness than to compel them to obedience from terror. The word mercy is coupled with the covenant, so that we may know that the reward which believers must expect does not depend on the merit of their works, since they have need of God’s mercy. We may, however, understand the phrase as follows: keeping the covenant of mercy, or the covenant founded on mercy, or the mercy which He covenanted.

When it is required of believers that they should love God before they keep His Commandments, we are thus taught that the source and cause of obedience is the love with which we embrace God as our Father. With respect to the “thousand generations,” it is better to refer to the Second Commandment, because it is a point which cannot be hurried over in a few words.

²²⁰ “Heb. And thou shalt know.” — Ainsworth. “Et scies.” — . And thou shalt know.” — Ainsworth. “Et scies.” — V..

²²¹ See on Deuteronomy 5:9, 10, , vol. 2, p. 110, , et seq..