Second, the threatenings of the law remind us what our sins deserve, though they are covered by the blood and righteousness of Jesus. Realizing afresh the punishment due to us, but received by Jesus in our place, moves us to shun sin, as we see in the prayer of Ezra: “After all that has come upon us for our evil deeds and for our great guilt, seeing that you, our God, have punished us less than our iniquities deserved . . . shall we break your commandments again . . . ?” (Ezra 9:13–14). Similarly, though we are not condemned for our sins, we are still disciplined by our heavenly Father—and the threat of consequences from His fatherly hand is a strong deterrent to unrighteousness (Ps. 89:30–33; 1 Cor. 11:32; Heb. 12:5–11).
Finally, in the words of the Westminster Confession, the promises of the law “show us God’s approbation of obedience, and what blessings we may expect upon the performance thereof; although not due to them by the law, as a covenant of works” (19.6). The Holy Spirit uses the great rewards promised to those who walk in the commandments of God to encourage us toward holiness (Pss. 19:11; 34:12–16; Eph. 6:2; 1 Peter 3:8–12). Paul makes this motivation explicit in 2 Corinthians 7:1: “Since we have these promises, beloved, let us cleanse ourselves from every defilement of body and spirit, bringing holiness to completion in the fear of God.”
Because saving faith responds to God’s Word by “yielding obedience to the commands, trembling at the threatenings, and embracing the promises of God for this life, and that which is to come” (WCF 14.2), the law of God effectually restrains the Christian’s remaining corruption. Or to use Calvin’s language, the law is “like a whip to an idle and balky ass, to arouse it to work. Even for a spiritual man not yet free of the weight of the flesh the law remains a constant sting that will not let him stand still” (Institutes, 2.7.12). To be sure, the law’s restraining effect is not the only or even the most important force in the life of the believer—the constraining love of Christ is the sweetest motivation of all (2 Cor. 5:14). Like a halter, however, God’s law does truly keep us away from evil paths and in the paths of righteousness for the sake of His name.
The law also restrains us for the sake of the world. How so? First, as the law restrains our ungodliness, we are made saltier salt and brighter light (Matt. 5:13–14). Our presence among the lost thus often powerfully restrains their depravity. Second, the recognition that our sin needs to be and is being restrained by the law is a humbling reality. This humility changes the way we relate to the lost. Rather than approaching them with the spirit of the Pharisee, we engage with the heart of the tax collector (Luke 18:9–14). Knowing that it is only by the grace of God (even through His law) that our sin has been subdued, our witness is gentle and gracious.
The next time you see that empty police car, remember the restraining power of the law of God in your life, and shine forth the lowly grace of Christ Jesus to all you meet.