J. I. Packer
Moses summoned all Israel and said: Hear, O Israel, the decrees and laws I declare in your hearing today. Learn them and be sure to follow them. DEUTERONOMY 5:1
Man was not created autonomous, that is, free to be a law to himself, but theonomous, that is, bound to keep the law of his Maker. This was no hardship, for God had so constructed him that grateful obedience would have brought him highest happiness; duty and delight would have coincided, as they did in Jesus (John 4:34; cf. Pss. 112:1; 119:14, 16, 47-48, 97-113, 127-128, 163-167). The fallen human heart dislikes God’s law, both because it is a law and because it is God’s; those who know Christ, however, find not only that they love the law and want to keep it, out of gratitude for grace (Rom. 7:18-22; 12:1-2), but also that the Holy Spirit leads them into a degree of obedience, starting with the heart, that was never theirs before (Rom. 7:6; 8:4-6; Heb. 10:16).
God’s moral law is abundantly set forth in Scripture, the Decalogue (the Ten Commandments), other Mosaic statutes, sermons by the prophets, the teaching of Jesus, and the New Testament letters. It reflects his holy character and his purposes for created human beings. God commands the behavior that he loves to see and forbids that which offends him. Jesus summarizes the moral law in the two great commandments, love your God and love your neighbor (Matt. 22:37-40), on which, he says, all the Old Testament moral instructions “hang” (depend). The moral teaching of Christ and his apostles is the old law deepened and reapplied to new circumstances—life in the kingdom of God, where the Savior reigns, and in the post-Pentecost era of the Spirit, where God’s people are called to live heaven’s life among themselves and to be God’s counterculture in the world.
Biblical law is of various sorts. Moral laws command personal and community behavior that is always our duty. The political laws of the Old Testament applied principles of the moral law to Israel’s national situation when Israel was a church-state, God’s people on earth. The Old Testament laws about ceremonial purity, diet, and sacrifice were temporary enactments for instructional purposes which the New Testament cancels (Matt. 15:20; Mark 7:15-19; 1 Tim. 4:3-5; Heb. 10:1-14, 13:9-10) because their symbolic meaning had been fulfilled. The juxtaposing of moral, judicial, and ritual law in the Mosaic books carried the message that life under God is to be seen and lived not compartmentally but as a many-sided unity, and also that God’s authority as legislator gave equal force to the entire code. However, the laws were of different kinds, with different purposes, and the political and ceremonial laws were of limited application, and it seems clear both from the immediate context and from the rest of his teaching that Jesus’ affirmation of the unchanging universal force of God’s law relates to the moral law as such (Matt. 5:17-19; cf. Luke 16:16-17).
God requires the total obedience of each total person to the total implications of his law as given. It binds “the whole man... unto entire obedience for ever”; “it is spiritual, and so reacheth the understanding, will, affections, and all other powers of the soul as well as the words, works, and gestures” (in other words, desiring must be right as well as doings, and Pharisaic externality is not enough: Matt. 15:7-8; 23:25-28); and the corollaries of the law are part of its content—“where a duty is commanded, the contrary sin is forbidden; and, where a sin is forbidden, the contrary duty is commanded” (Westminster Larger Catechism Q.99).