The key text of Deuteronomy is clear. “Hear, O Israel: The Lord our God, the Lord is one. You shall love the Lord your God with all your heart and with all your soul and with all your might. And these words that I command you today shall be on your heart” (6:4-6).

As Jesus says, “This is the great and first commandment” (Matt. 22:38). Deuteronomy sets forth this love in both broad strokes and minute detail for the Old Testament economy to follow—and for the New Testament economy dawning with the advent of Christ. This love is a matter of heart: “You shall love the Lord your God with all your heart.” This love also involves heartfelt submission to God’s commands: “These words that I command you today shall be on your heart.”

Moses emphasizes these two aspects of life before God: (1) love expressed through (2) observance of God’s commands. “And now, Israel, what does the Lord your God require of you, but to fear the Lord your God, to walk in all his ways, to love him, to serve the Lord your God with all your heart and with all your soul?” (Deut. 10:12). “You shall therefore love the Lord your God and keep his charge, his statutes, his rules, and his commandments always” (11:1). We hear echoes of our Lord Jesus Christ, “If you love me, you will keep my commandments” (John 14:15); and of the Apostle John, “For this is the love of God, that we keep his commandments” (1 John 5:3).

However, a profound problem exists. After years of experience in the wilderness, Moses knows the hearts of the people. By God’s grace, Moses also knows that God will remedy the defect in their hearts. “The Lord your God will circumcise your heart and the heart of your offspring, so that you will love the Lord your God with all your heart and with all your soul, that you may live” (Deut. 30:6).

Here, circumcision of the heart is equivalent to new birth and the promise of the new covenant. “I will give you a new heart, and a new spirit I will put within you. And I will remove the heart of stone from your flesh and give you a heart of flesh. And I will put my Spirit within you, and cause you to walk in my statutes and be careful to obey my rules” (Ezek. 36:26-27). All of this is in accord with God’s love for His people. “The Lord set his heart in love on your fathers and chose their offspring after them, you above all peoples, as you are this day” (Deut. 10:15).

But there is a seeming difficulty. Reception of God’s love appears to depend upon the people’s obedience: “Know therefore that the Lord your God is God, the faithful God who keeps covenant and steadfast love with those who love him and keep his commandments” (Deut. 7:9). But why would any people be faithful and obedient? Listen again to Moses: “It was not because you were more in number than any other people that the Lord set his love on you and chose you, for you were the fewest of all peoples, but it is because the Lord loves you and is keeping the oath that he swore to your fathers” (vv. 7-8). J. G. McConville explains, “The full statement of covenant here, therefore, is of faithful love returned by faithful people” (Deuteronomy, p. 158). In other words, “We love because he first loved us” (1 John 4:19).

This good news is the gospel according to Moses, which we cherish and by which we live.