Deuteronomy 4:39 (ESV) …. “Know therefore today, and lay it to your heart, that the Lord is God in heaven above and on the earth beneath; there is no other.”
When you’re raising small children, you use rewards and punishments to teach them to obey; but when they get older, you hope that character and love will motivate them to shun evil and do what’s right. When Israel turned from the true and living God and began to worship idols, they were sinning against God’s grace and love. The Lord hadn’t chosen any other nation and given it His covenant, nor had He spoken to any other nation and given it His holy law. God had led His people and cared for them from the days of Abraham to the time of Moses, and He had done this for no other nation. Why? It wasn’t because Israel deserved these blessings but because of God’s everlasting love (v. 37; see 7:7–8, 13; 23:5).
God doesn’t want His children obeying Him just to get blessings or to avoid chastening, but because they love Him from the heart. The word “heart” is mentioned more than forty times in Moses’ speech, and the Shema (6:4–5) emphasizes love for the Lord. (See also 10:12; 11:1, 13, 22; 13:3; 19:9; 30:6, 16, 20.) When Moses gave the law to the older generation at Sinai, the emphasis was on the fear of the Lord (Ex. 19:10–25; 20:20), but his application of the Law to the new generation magnifies God’s love for Israel and the importance of Israel loving the Lord. They were now to be a mature people who obeyed God from the heart. The Lord is a merciful God (Deut. 4:31), but we shouldn’t tempt Him because He is also a jealous God (v. 24).
As evidence of God’s love and mercy, Moses set apart three “cities of refuge” on the east side of the Jordan, to which people who accidentally killed somebody could flee and get justice and find protection (vv. 41–43).