I said, "I will keep Your words, O Lord." Moses said (Deuteronomy 7:6), "For you are a holy people to the Lord your God." It is written here not "in you" but "in you the Lord your God has chosen." Even one of you is more beloved before the Holy One, blessed be He, than all the nations of the world.
And so Isaiah said (Isaiah 40:17), "All the nations are as nothing before Him, etc." Therefore, it is said, "In you the Lord your God has chosen." He chose you, and you chose Him. And so it says (Psalm 135:4), "For Jacob, He chose for Himself, etc." The Lord chose Jacob, and Jacob chose Him. And so it says (Song of Songs 6:3), "I am my beloved's, etc." He says to you, "You are My portion," and you say to Him (Lamentations 3:24), "My portion, O Lord."
And so He says, "You are My portion, and I am yours." And what do I ask of you? Things that are said (Deuteronomy 6:6-7), "And these words which I command you today shall be in your heart, etc." And so it says (Deuteronomy 11:18), "Therefore, you shall lay up these words of mine in your heart, etc." Therefore, it is said, "I said, 'I will keep Your words, etc.'" "I entreat Your favor with all my heart; be gracious to me according to Your promise" (Exodus 33:19), "and I will have compassion on whom I will have compassion, etc."