The Reason For Doing This Is because In Compassion and Mercy He Has Chosen Them To The End That They Are His Holy (Set Apart For Himself) People And Has Set His Love On Them (Deuteronomy 7:7-11).
In this passage the love and faithfulness of God is accentuated, and it is stressed that He loves them, not because they deserve it or were worthy, but simply because He has sovereignly set His love on them and also for their fathers' sakes. Thus they can be sure that He will reveal His faithfulness by responding to those who are faithful to Him while repaying those who become unfaithful.
Analysis in the words of Moses:
a Yahweh did not set his love on you (you all), nor choose you, because you were more in number than any people, for you were the fewest of all peoples (Deuteronomy 7:7).
b But because Yahweh loves you all, and because He would keep the oath which He swore to your fathers, has Yahweh brought you out with a mighty hand, and redeemed you out of the house of bondage, from the hand of Pharaoh king of Egypt (Deuteronomy 7:8).
c Know therefore that Yahweh your God, He is God, the faithful God (El) (Deuteronomy 7:9 a).
c He keeps covenant and lovingkindness with those who love Him and keep His commandments to a thousand generations (Deuteronomy 7:9 b).
b And those who hate Him He repays to their face, to destroy them. He will not be slack to him who hates Him, He will repay him to his face (Deuteronomy 7:10).
a You shall therefore keep the commandment, and the statutes, and the ordinances, which I command you this day, to do them (Deuteronomy 7:11).
We note in ‘a' that Yahweh showed great favour to them by setting His love on them so that in the parallel they are to respond by keeping His commandments give to them this day, and doing them. In ‘b' Yahweh loves them and because He would keep His oath to their fathers has delivered them from bondage in Egypt, but in the parallel those who hate Him He repays to their face. In ‘c', because He is Yahweh, the faithful God, in the parallel He is faithful to His covenant and reveals His covenant love to His people permanently as long as they too are faithful.
‘ Yahweh did not set his love on you (ye all), nor choose you (ye), because you (ye) were more in number than any people, for you (ye) were the fewest of all peoples,'
Here we have emphasised that Yahweh has set His love on them. And note that Moses expects them to be aware of that fact. They have good reason to know that they are the beloved of Yahweh.
He stresses that Yahweh did not set His love on them or choose them because they were so many, or because they were a more numerous people than others, for they were not. That was the way men looked at things. When He had first chosen them they had been the fewest of all peoples, wandering through Canaan with their herds and flocks, seen as strangers passing by, and then settling in Egypt as a band of resident aliens. They were the weak, the foolish, the despised (compare 1 Corinthians 1:27-29). It was nothing in them that had occasioned His love and choosing. It was rather an act of divine grace, of unmerited goodness and power, because they were descendants of, or had become connected with the descendants of, His faithful and beloved servant Abraham.
‘ But because Yahweh loves you (ye all), and because he would keep the oath which he swore to your (your) fathers, has Yahweh brought you out with a mighty hand, and redeemed you (ye) out of the house of bondage, from the hand of Pharaoh king of Egypt.'
Rather, therefore, Yahweh chose them because He loved them. The final reason for that is unstated. It was simply the determined act of God. It was true that it was for their father's sakes, and then for their own sake because of their response to Him in the covenant, and because He was determined to keep His oath to their fathers, to Abraham, Isaac and Jacob. But over and above it all it was because He had chosen for His love to reach out to them. And that was why He had redeemed them out of the house of bondage, from the hand of Pharaoh, king of Egypt.
Here in this verse we have important theological overtones. Firstly that Yahweh loved His people. They were chosen because He loved them, and they were chosen because of the oath that He had sworn to their fathers. And secondly that it was because of these things that He had bought them, He had ‘redeemed' them, a piteous people, out from under bondage, delivering them from the hand of Pharaoh. The connection of ‘redeemed' with ‘bondmen in bondage' supports the idea that we see it as the paying of a price, even if that price was the exertion of His power to bring Pharaoh in submission to His will.
And we too, if we are Christ's, are chosen in His love. The thought that God has set His love on us from all eternity (Ephesians 1:4) can only humble us and yet flood our hearts with praise and gratitude. For we are God's true Israel, being the continuation of the old spiritual Israel (Galatians 3:29; Ephesians 2:11-22; Romans 11:17-24). And the Scripture makes quite plain that having chosen us and loved us He has justified us in Christ, and will raise us to final glorification (Romans 8:29-30). How then can we also fail to seek to fulfil all His commandments and rid ourselves of all that is displeasing to Him?
‘ Know therefore that Yahweh your (thy) God, he is God, the faithful God (El), who keeps covenant and lovingkindness with those who love him and keep his commandments to a thousand generations, and repays those who hate him to their face, to destroy them. He will not be slack to him who hates him, he will repay him to his face.'
By consideration of this (‘therefore') they could know that Yahweh is God (He defeated Pharaoh, god of Egypt, and all his supporting gods, treating them as nothings), that He is the faithful God, faithful to His past covenants and to those on whom He has set His love in the past, and that He keeps covenant with and shows gracious mercy towards those who love Him and keep His commandments. Note that loving Him comes prior to the keeping of His commandments. The keeping of the commandments results from that love. This is not to be seen as abiding by strict rules out of fear of the consequences, but as lovingly responding to Yahweh's requirements because they love Him for what He has done for them. (Compare Luke 7:41-42).
“To a thousand generations.” That is, to numberless generations. His faithfulness, love and compassion go on and on. (Compare how ‘a thousand years' means numberless years - Psalms 90:4; Ecclesiastes 6:6).
“And repays those who hate him to their face, to destroy them. He will not be slack to him who hates him, he will repay him to his face.” But while on the one hand there is love and compassion, on the other there is aversion to sin and to those who reject His covenant, those who thus show that they ‘hate' Him. These, such as the Canaanites, He will destroy. This fact is stressed. He is not slack and slovenly about dealing with sin, He does it openly and readily in the face of the sinner. Therefore let all who would sin beware. There is no room in His land for sin.
‘ You shall therefore keep the commandment, and the statutes, and the ordinances, which I command you this day, to do them.'
Because of that (‘therefore'), because he is compassionate and merciful to those who look to Him, and harsh with sinners, they are to keep His commandment, and the statutes and ordinances that He commands them this very day, as they will shortly be unfolded.