14. The Law as Mirror
14.1 Purpose of the Ten Commandments
The moral law—epitomised in the Decalogue (Exodus 20:1–17)—reveals God’s holiness and humanity’s deviation from it. The Law was never intended primarily as a means of salvation but as a disclosure of divine righteousness. Paul declares, “The law is holy, and the commandment is holy and just and good” (Romans 7:12 NRSV). It provides an objective moral standard by which actions are judged and consciences awakened. Calvin (1559) likened the Law to a mirror in which humans “discover the stains of their own corruption.”
14.2 ‘By the Law Comes Knowledge of Sin’
Romans 3:20 states, “Through the law comes knowledge of sin.” This epistemological function exposes guilt but cannot remove it. Augustine (1998) observed that the Law accuses but does not heal; it “commands faith” yet leaves humankind longing for grace. The Law thus performs a pedagogical role—identifying the disease of sin and pointing to the remedy in Christ (Galatians 3:24).
14.3 Inability of the Law to Save
While the Law reveals sin, it lacks the power to justify: “No one will be justified before Him by the works of the law” (Romans 3:20). Its holiness highlights humanity’s incapacity. Luther (1520) described this as the “second use of the Law,” whose purpose is to drive the sinner to grace. Hence, salvation lies not in obedience to the letter but in regeneration through the Spirit (Romans 8:2–4). The mirror exposes; only Christ cleanses.
15. Conscience and the Witness of the Spirit
15.1 The Moral Law Written on the Heart
Even apart from explicit revelation, humans possess moral awareness. Paul affirms that Gentiles “show that what the law requires is written on their hearts, while their conscience also bears witness” (Romans 2:14–15). Conscience functions as an internal tribunal that approves or condemns actions according to an innate sense of right and wrong (Aquinas, 1265–1274). However, conscience is not infallible; when corrupted, it can be seared or darkened by habitual sin (1 Timothy 4:2). Thus natural law prepares for—but cannot replace—the illumination of divine revelation.
15.2 Conviction by the Holy Spirit
Ultimate recognition of sin arises through the work of the Holy Spirit. Jesus taught, “When He comes, He will prove the world wrong about sin and righteousness and judgement” (John 16:8–9). The Spirit transforms abstract guilt into personal conviction, revealing sin as unbelief and self-centredness. Barth (1932) notes that the Spirit’s conviction is simultaneously judgement and grace: it exposes wrongdoing yet invites repentance. Without this divine illumination, human moral sense remains partial and defensive (1 Corinthians 2:14).
The Spirit’s ministry therefore completes what the Law and conscience begin. Law defines transgression; conscience echoes its verdict; the Spirit reveals sin’s true depth and offers renewal through faith in Christ (Romans 8:15–16). Recognition of sin thus becomes the threshold of salvation.
References
- Aquinas, T. (1265–1274) Summa Theologiae, trans. Fathers of the English Dominican Province. London: Burns Oates, 1920 edn.
- Augustine (1998) Confessions, trans. H. Chadwick. Oxford: Oxford University Press.
- Barth, K. (1932) Church Dogmatics II/1: The Doctrine of God. Edinburgh: T & T Clark.
- Calvin, J. (1559) Institutes of the Christian Religion. Grand Rapids: Eerdmans, 1989 edn.
- Luther, M. (1520) Works, Vol. 31. Philadelphia: Fortress Press, 1960 edn.
- The Holy Bible (NRSV, 2011). London: HarperCollins.