"Therefore the Law has become our tutor to lead us to Christ, so that we may be justified by faith."
— Galatians 3:24 (NASB95)

"Why the Law then?" (Galatians 3:19) — Paul's own question, forced by his own gospel: if righteousness was always by promise and faith, what was the Law for? Scripture's answer is consistent and multi-sided: the Law was given to reveal God's holiness, to expose and even amplify sin into legally chargeable form, to shut every mouth and shut up all under sin, to restrain evil in the interim, and — its crowning office — to escort Israel to Christ. What the Law was never given to do is justify or sanctify: "by the works of the Law no flesh will be justified in His sight" (Romans 3:20). Misassigning the Law's purpose produces both legalism (asking it to save) and antinomianism (concluding it was pointless); reading its job description rightly makes it, in Paul's words, "good, if one uses it lawfully" (1 Timothy 1:8).

Passages studied: Romans 3:19–20; Romans 7:7–13; Romans 5:20 with Galatians 3:19; Galatians 3:21–25; 1 Timothy 1:8–11.

Key Passages

Romans 3:19–20 — The Mouth-Stopper

Romans 3:19–20

NASB95: "Now we know that whatever the Law says, it speaks to those who are under the Law, so that every mouth may be closed and all the world may become accountable to God; because by the works of the Law no flesh will be justified in His sight; for through the Law comes the knowledge of sin."

Climaxing his indictment of humanity (Romans 1:18–3:18), Paul states the Law's first purpose in courtroom terms: "that every mouth may be closed" — φραγῇ (phragē, from phrassō, Strong's G5420, "to stop, block, silence"; BDAG, s.v.) — every self-defense plea gagged, "all the world... ὑπόδικος (hypodikos, G5267, 'answerable, liable to judgment' — a legal term: standing guilty before the court)." Through the Law comes ἐπίγνωσις ἁμαρτίας — the knowledge of sin: the Law is the mirror that shows the dirt (James 1:23–25) and the plumb line that shows the wall's lean (Amos 7:7–8); it measures, it cannot wash. A mirror is a gift — but only a fool scrubs his face with it. What the Law can never be is the means of justification — "by the works of the Law no flesh will be justified" (echoing Psalm 143:2) — a verdict rendered not because the standard was low but because every defendant is a sinner.

Romans 7:7–13 — Sin Exposed as Sin

Romans 7:7–13

NASB95 (vv. 7b, 12–13a): "...I would not have come to know sin except through the Law; for I would not have known about coveting if the Law had not said, 'YOU SHALL NOT COVET'... So then, the Law is holy, and the commandment is holy and righteous and good. Therefore did that which is good become a cause of death for me? May it never be! Rather it was sin, in order that it might be shown to be sin..."

Paul's autobiography of the Law at work: the tenth commandment — the one aimed at desire, untriable by human courts — found him out. Sin, "taking opportunity (ἀφορμή, aphormē, G874 — a military base of operations) through the commandment," produced in him "coveting of every kind" (v. 8): the forbidden thing became, to fallen flesh, the fascinating thing (the dynamic every parent knows from the words "do not touch"). The fault lies not in the Law — Paul triple-crowns it "holy and righteous and good" (v. 12) — but in sin, which the commandment provokes into the open "so that through the commandment sin would become utterly sinful" (v. 13): the Law is the physician's dye that makes the hidden tumor visible, the ultraviolet light that exposes what the darkened room concealed. This is diagnostic mercy: a disease named is a disease treatable — by another remedy than the diagnostic itself (Romans 7:24–25 — "Who will set me free...? Thanks be to God through Jesus Christ our Lord!").

Romans 5:20 & Galatians 3:19 — Added to Increase the Trespass

Romans 5:20; Galatians 3:19

NASB95 (Rom 5:20): "The Law came in so that the transgression would increase; but where sin increased, grace abounded all the more."

The Law's strangest office, stated without flinching: it "came in" — παρεισῆλθεν (pareisēlthen, "entered alongside," G3922 — supplementary, parenthetical to the promise-line from Abraham to Christ) — "so that the transgression would increase." Not that God manufactures sin, but that sin under explicit command becomes παράβασις (parabasis, G3847, "transgression" — the deliberate stepping across a drawn line; BDAG, s.v.; cf. Romans 4:15 — "where there is no law, there also is no violation"): the Law converts diffuse rebellion into itemized, chargeable, undeniable trespass — sin with a paper trail. And the stated end of the amplification is doxological: "where sin increased, grace abounded all the more" (ὑπερεπερίσσευσεν, hyperepesisseusen — super-abounded) — the flood-marks of sin become the measuring posts of grace. God ordained the Law's exposing work precisely so that grace, when it came, would be seen for what it is.

Galatians 3:21–25 — The Tutor to Lead Us to Christ

Galatians 3:21–25

NASB95 (vv. 23–25): "But before faith came, we were kept in custody under the law, being shut up to the faith which was later to be revealed. Therefore the Law has become our tutor to lead us to Christ, so that we may be justified by faith. But now that faith has come, we are no longer under a tutor."

The Law's crowning purpose, in two images. First, custody: "kept in custody" (ἐφρουρούμεθα, from phroureō, G5432 — garrisoned, guarded) and "shut up" (συγκλειόμενοι, from synkleiō, G4788 — locked in on all sides, v. 22 — "Scripture has shut up everyone under sin, so that the promise by faith in Jesus Christ might be given to those who believe"): the Law as protective confinement with one exit, and the exit is Christ. Second, the παιδαγωγός (paidagōgos, Strong's G3807) — not "schoolmaster" in the modern sense but the household slave who supervised a boy's conduct, escorted him to school, and whose authority ended at the boy's coming of age (BDAG, s.v. "παιδαγωγός"; the custom is abundantly documented in Greco-Roman sources — see the overview in Keener, IVP Bible Background Commentary: New Testament, 2nd ed., on Gal 3:24). The Law disciplined Israel's minority and walked her to the Teacher; "but now that faith has come, we are no longer under a tutor" (v. 25) — the escort's job, faithfully done, is over. To return to the paidagōgos after meeting the Teacher is not maturity but regression — the whole burden of Galatians (Galatians 4:9; 5:1). Fee stresses that vv. 23–25 are salvation-historical: an epoch ("before faith came... now that faith has come"), not merely an individual's psychology (Fee, Galatians, Pentecostal Commentary Series, Deo, 2007, on 3:23–25).

1 Timothy 1:8–11 — The Lawful Use of the Law

1 Timothy 1:8–11

NASB95 (vv. 8–9a): "But we know that the Law is good, if one uses it lawfully, realizing the fact that law is not made for a righteous person, but for those who are lawless and rebellious..."

Paul's mature summary: the Law is καλός (kalos, "good") — if used νομίμως (nomimōs, G3545, "lawfully, in accordance with its design"). Its design-target is stated: "not... a righteous person, but... the lawless and rebellious" — followed by a vice-list that tracks the Decalogue's order (striking father and mother — the fifth; murderers — the sixth; immoral men and homosexuals — the seventh; kidnappers, i.e., man-stealers — the eighth cf. Exodus 21:16; liars and perjurers — the ninth), all measured against "sound teaching according to the glorious gospel" (vv. 10–11). The Law retains a standing ministry: to convict the openly rebellious and expose sin as sin — the surgeon's scalpel, not the patient's food. Its unlawful uses are equally clear from the context (v. 7 — would-be "teachers of the Law" using it for speculation and self-justification): as a ladder to God, a badge of superiority, or a diet for the justified. The believer, counted righteous in Christ, is no longer the Law's target — he now serves "in newness of the Spirit and not in oldness of the letter" (Romans 7:6).

What the Law Was Never Given to Do

The counter-list guards the doctrine. The Law was never given to justify (Galatians 2:16; Acts 13:39); never able to impart life — "if a law had been given which was able to impart life, then righteousness would indeed have been based on law" (Galatians 3:21); never the means to the Spirit (Galatians 3:2 — "did you receive the Spirit by the works of the Law, or by hearing with faith?"); never the engine of sanctification (Galatians 3:3 — "having begun by the Spirit, are you now being perfected by the flesh?"; Romans 8:3–4 — what the Law could not do, God did, that its requirement be fulfilled in Spirit-walkers); and never able to perfect the conscience (Hebrews 10:1–4). Asking the Law to do these things is not honoring it but overloading it — and, Paul says bluntly, nullifying grace: "if righteousness comes through the Law, then Christ died needlessly" (Galatians 2:21).

Conclusion

The Law's God-assigned portfolio: reveal the Holy One's character; name sin, expose it, provoke it into the open, and convert it into chargeable transgression; silence every boast and lock all humanity into a custody whose single door is Christ; restrain the lawless in the meantime; and escort the heir, through his minority, to the Son who justifies by faith. Every purpose is preparatory, diagnostic, or custodial — none is curative; the Law is the tutor, never the Father; the mirror, never the bath; the X-ray, never the surgery. Used lawfully it still does its ancient work in evangelism and conscience; used unlawfully it nullifies the grace it was designed to magnify. Its own testimony, rightly heard, has always been the tutor's word at the schoolhouse door: you have arrived — here is the Teacher (Luke 24:44; Romans 10:4).