Many attempts have been made to portray the historical old (Sinai) covenant as a covenant of laws, rules, and regulations in contrast to the new covenant, deemed to be a covenant of love. But such attempts fail upon examination. Many scholars consider Deuteronomy to be Israel’s covenant book, as it contains Moses’ reiteration of God’s covenant with Israel and is structured like the Near Eastern treaties of Moses’ day (see, for example, Meredith Kline’s book, Treaty of the Great King). Significantly, Deuteronomy contains more references to God’s love for people and invitations for them to love Him and others than does any other book of the Bible, other than Psalms, Hosea, John, and 1 John.
The first reference in the Bible to God loving people occurs in the second of the Ten Commandments, which depicts God “showing lovingkindness [Heb, hesed] to thousands . . . who love Me and keep My commandments” (Deut. 5:10, NASB; Exod. 20:6, NASB). (Modern translations, including conservative ones, characteristically translate the Hebrew hesed as “lovingkindness” [NASB], “steadfast love” [ESV, NRSV], “love” [NIV], “faithful love” [NJB], “loyal love”/“covenant faithfulness” [NET Bible], and so on, rather than “mercy,” as do KJV and NKJV.) God’s love for His people, the “fatherless,” “widows,” and “strangers,” is repeatedly restated throughout the remainder of Deuteronomy (7:8, 9; 10:15, 18; 24:19; 27:19). As noted above, such emphasis on God’s love for humanity rarely occurs elsewhere in Scripture, but once expressed in the Sinai covenant it became Scripture’s dominant theme.
The revelation of God’s love for humans overwhelmed the Old Testament believer, even as it does the New Testament believer. For example, Psalm 136 repeats this frame 26 times—“His love [Heb. hesed] endures forever” (NIV)—a phenomenon not found anywhere in the New Testament. And God’s love motivated the Old Testament believer’s response of obedience.
The Shema (Deut. 6:4–9), expressed by Moses following his reiteration of the Ten Commandments (5:2–22), contained the core motivational principle for the believer’s response to God’s commandments and the gospel: “You shall love the LORD your God with all your heart, with all your soul, and with all your strength” (6:5, NKJV). Jesus called it “the first and great commandment” (Matt. 22:38), meaning the principle that pervaded all interactions and relationships in heaven before sin entered. It will return fully in the new earth era, when the prohibitive form of the commandments will no longer be needed as they are now, during the era of sin; then the positive form of the commandments will pervade and actuate each heart.
Thereafter, the appeal in Deuteronomy, the Old Testament covenant book, was: love God and keep His commandments. Notice the order: (1) love God and (2) keep His commandments. In the divine economy, obedience to God’s commandments was never a begrudging, dutiful compliance, but rather “the service and allegiance of love” (Steps to Christ, 60). Throughout Deuteronomy the appeal for covenant faithfulness is anchored first in love; obedience to the commandments of God follows (see 7:9 [cf., John 14:21]; 10:12–19 [cf., John 13:34]; 11:1, 13-14, 22–24 [cf., John 15:10]; 13:3, 4; 19:8, 9; 30:6 [cf., Phil 2:13], 16, 19, 20). For that to occur, in that order (first love, then obedience), He must write His law in our hearts, which is His goal and delight to do.
The apostle Paul’s mantra, “Love is the fulfillment of the law” (Rom. 13:10, NKJV), was established in the Sinai covenant. This is another reason why the old and new covenants were equal to each other at the most fundamental level.