And thou shalt know that the Lord thy God, he is a strong and faithful God, keeping his covenant and mercy to them that love him, and to them that keep his commandments, unto a thousand generations:

“לאלף דור TO A THOUSAND GENERATIONS — But elsewhere (5:10) it states: to thousands of generations! The explanation is: Here where it is connected with (refers to) "those who keep His commandments" it states that God's grace is extended to a thousand generations; but there where it is associated with "those who love Him" it states that it is extended to thousands of generations (Sotah 31a); לאהביו are those who do the commandments out of love. ולשמרי מצותיו are those who do them out of fear.”

“KNOW THEREFORE from the [circumstances of the] departure from Egypt THAT THE ETERNAL THY G-D, HE IS G-D Who created heaven and earth, as I have explained. And know furthermore from this that He is THE FAITHFUL G-D Whose word shall not return void, and WHO KEEPETH THE COVENANT AND MERCY WITH THEM THAT LOVE HIM, AND KEEP HIS COMMANDMENTS, who fear His Name, TO A THOUSAND GENERATIONS of their seed, just as He kept for you the covenant of your fathers. And know further that He repayeth them that hate Him the recompense of their wickedness to the face of each one of them to destroy them, just as He destroyed the Egyptians and did not delay [in bringing punishment] to them. Now this attribute that he mentioned is true forever. Thus although there is a wicked man that prolongeth his life in his evil-doing, it happens to him only because of this above-mentioned attribute that He is the Keeper of Mercy, and he [the wicked] has done some good which must be recompensed. If so, there are among the attributes of the Holy One, blessed be He, but two ways [of dealing with people]: He repays good for good, and evil for evil. It is possible that those that hate Him [mentioned here as destined to be destroyed without delay] are those confirmed sinners who deny His existence and have no merit at all. As the Rabbis have said: “Rabbi Yashiyah said: Because of three things the Holy One, blessed be He, is long-suffering to the wicked in this world: they may repent, or they have observed commandments for which the Holy One, blessed be He, repays them their recompense in this world, or perhaps righteous people will descend from them. For so we find that He was long-suffering with Ahaz, and Hezekiah came from him; so also to Amon,, 21:19-22. and Josiah came from him; and so also to Shimei, and Mordecai came from him.” Thus all these [three above categories] are not included in [the term] those that hate Him. Now there is a secret in the expression ‘el panav’ (to his face) [And He repayeth ‘them’ that hate Him ‘el panav’ — “to his face”]], why does it change to the singular [to ‘his’ face, to destroy ‘him’]? Ramban alludes to the secret of the transmigration of the soul, so that at some future generation the recompense is still to “the face” of the sinner after he has been rewarded for the good he has done (Abusaula). as applying to a wicked man who has a good [i.e., a happy and prosperous] life. And then he returns to say, Thou shalt therefore keep the commandment etc., meaning: “therefore keep the commandment, and the statutes, and the ordinances so that you should not be among those who hate Him, who are destroyed, but instead you should be of those that love Him and keep His commandments who are remembered for good and for life.” Eikev”

“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 Exo 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.”

“By this was Israel to know that Jehovah their God was the true God, the faithful God, who keeps His covenant, showing mercy to those who love Him, even to the thousandth generation, but repaying those who hate Him to the face. This development of the nature of God Moses introduces from Exo 20:5-6, as a light warning not to forfeit the mercy of God, or draw upon themselves His holy wrath by falling into idolatry. To this end He emphatically carries out still further the thought of retribution, by adding להאבידו, "to destroy him" (the hater), and וגו יאהר לא, "He delays not to His hater (sc., to repay him); He will repay him to his face." "To the face of every one of them," i.e., that they may see and feel that they are smitten by God (Rosenmller).”