The Law Was a Guardian, Not a Savior Text: Galatians 3:19-22
Introduction: Getting the Story Straight
The book of Galatians is a cannonade against a particular kind of confusion, a confusion that is perennial in the church. It is the confusion that arises when men try to mix two different ways of relating to God. One way is the way of promise, of grace, of faith. The other is the way of law, of performance, of works. The Judaizers who had infiltrated the Galatian churches were telling these new Gentile believers that faith in Jesus was a fine start, but that it needed to be completed. It needed the finishing touches of the Mosaic law, beginning with circumcision. They were trying to pour the new wine of the gospel back into the old wineskins of the Sinai covenant.
Paul has spent the better part of three chapters dismantling this error brick by brick. He has argued from his own testimony, from the Galatians' own experience of the Spirit, and from the foundational story of Abraham. The central point is this: God made a promise to Abraham and his seed, which is Christ, 430 years before the law was ever given. The inheritance comes through that promise, received by faith. The law, coming centuries later, cannot possibly annul or set aside that prior, unconditional promise. God doesn't do bait-and-switch.
But this raises an obvious and necessary question, one that Paul anticipates. If the promise is everything, if justification is by faith from start to finish, then what was the point of the law? Why did God bother with all the sound and fury at Mount Sinai? Why the Ten Commandments? Why the sacrificial system? Why the civil code? Was it a mistake? A detour? A failed experiment? If the law cannot justify, what is its purpose? This is the question Paul addresses in our text today. And his answer is crucial for understanding not only the Old Testament, but also the very nature of the gospel itself. If we get the law wrong, we will inevitably get the gospel wrong.
The Text
Why the Law then? It was added because of trespasses, having been ordained through angels by the hand of a mediator, until the seed would come to whom the promise had been made. Now a mediator is not for one person only, whereas God is one. Is the Law then contrary to the promises of God? May it never be! For if a law had been given which was able to impart life, then righteousness would indeed be by law. But the Scripture has shut up everyone under sin, so that the promise by faith in Jesus Christ might be given to those who believe.
(Galatians 3:19-22 LSB)
The Law's Temporary Job Description (v. 19-20)
Paul begins by asking the question that is on everyone's mind and gives a direct, multi-part answer.
"Why the Law then? It was added because of trespasses, having been ordained through angels by the hand of a mediator, until the seed would come to whom the promise had been made." (Galatians 3:19 LSB)
First, what was the law's purpose? "It was added because of trespasses." The word "added" is key. The law was not the main event; it was a codicil, an addendum to the covenant story that had already been running for centuries on the basis of promise. It was inserted for a specific reason. And that reason was "trespasses." The law was given to deal with sin. But how? Not by removing it, but by revealing it. The law's job was to make sin exceedingly sinful (Rom. 7:13). It was given to take the general, vague rebellion of humanity and bring it into sharp, legal focus. It defines the property lines so that you know what trespassing is. It turns up the lights in a filthy room so you can see just how much grime there is. The law doesn't clean the room; it exposes the need for a cleaner. It diagnoses the disease; it doesn't provide the cure. It provokes sin, aggravates it, and makes it undeniable, so that men might stop making excuses and see their need for a savior.
Second, notice the law's expiration date. It was added "until the seed would come." The law was a temporary provision. It was a guardian, a tutor, a babysitter for God's people in their minority. It was never intended to be the permanent arrangement. Its authority was real, but its tenure was limited. It was designed to function for a specific period of redemptive history, the period between Moses and Christ. Once the heir, the Seed, Jesus Christ, came of age and arrived on the scene, the guardian's role was fulfilled.
Third, notice the law's delivery method. It was "ordained through angels by the hand of a mediator." This is a crucial point Paul is making about the nature of the Sinai covenant. It was a mediated covenant. God did not give it to Israel directly, as He gave the promise to Abraham. Instead, it was delivered through intermediaries: angels, and then Moses. This distance is deliberate. The promise to Abraham was a direct, unilateral declaration from God. "I will..." But the law was a bilateral covenant, a negotiation. "If you... then I will..." This is what a mediator is for. A mediator stands between two parties.
"Now a mediator is not for one person only, whereas God is one." (Galatians 3:20 LSB)
This is a dense but powerful verse. A mediator implies at least two parties. Moses stood between God and Israel. But the promise was not like that. The promise was a monologue, not a dialogue. God made the promise to Abraham, and He swore by Himself because there was no one greater to swear by (Heb. 6:13). The promise depends on the character of the one making it. "God is one." He is singular, undivided, and utterly self-consistent. The promise flows directly from His unchanging nature. The law, with its mediators and its two-party structure, is inherently less direct, less ultimate. Paul is subtly downgrading the law in comparison to the promise. The promise is a straight line from God to us. The law was a more complex arrangement, necessary for a time, but not the ultimate thing.
The Law as a Prison Guard (v. 21-22)
Paul anticipates the next logical objection. If the law is temporary and mediated, does that mean it's bad? Is it working against God's promises?
"Is the Law then contrary to the promises of God? May it never be! For if a law had been given which was able to impart life, then righteousness would indeed be by law." (Galatians 3:21 LSB)
Paul's answer is an emphatic "May it never be!" The law is not the enemy of the promise. They are not in conflict because they have two completely different job descriptions. The law was never intended to give life. If there was a law anywhere, on any planet, that could make dead sinners alive, then God would have used it. If salvation could have come through a set of rules, the incarnation would have been unnecessary. Christ's death would have been a tragic waste. But no law can do that. A law can tell you what life looks like, but it cannot impart the life itself. It can describe righteousness, but it cannot produce it in a fallen heart.
The law and the promise are working toward the same ultimate end, but from different angles. Think of it this way. The promise is the rescue helicopter. The law is the man on the ground with a flare gun, showing the helicopter where the desperate, stranded people are. The flare doesn't rescue anyone, but it's not contrary to the rescue. It's an essential part of it. The law's job is to make us look up.
So what is the law's specific function in service to the promise? Paul tells us in the final verse.
"But the Scripture has shut up everyone under sin, so that the promise by faith in Jesus Christ might be given to those who believe." (Galatians 3:22 LSB)
The Scripture, meaning the Old Testament law, has a specific ministry. It acts as a prison guard. It has "shut up everyone under sin." The Greek word means to enclose, to lock up, to imprison. The law finds the whole world guilty and locks the door. It puts all of humanity, Jew and Gentile alike, into the same jail cell. It strips us of all our excuses, all our claims to self-righteousness. It takes away every other escape route. It forces us to acknowledge our condition: we are sinners, we are trapped, and we cannot get ourselves out.
But this is a gracious imprisonment. The law shuts us up in the prison of our sin for a glorious purpose: "so that the promise by faith in Jesus Christ might be given to those who believe." The law locks every other door so that we will finally notice the one door that has been left open. That door is the promise of God. The law herds us, corners us, and corrals us into a place of desperation where the gospel can finally be heard as good news. When you know you are sick, you want a doctor. When you know you are drowning, you want a lifeguard. And when the law has done its work and shown you that you are a guilty, condemned sinner, you are finally ready for a Savior.
The law shuts us up to the promise. It locks us in so that God can break in. It declares us bankrupt so that we might receive the free gift of infinite riches. The law is the black velvet upon which the diamond of the gospel shines most brightly. It is not contrary to the promise; it is the promise's advance man, its setup crew, its most effective servant.
Conclusion: From Prison to Promise
So we must understand the law's role correctly. It is good, holy, and just. But it is a mirror, not a fountain. It is a diagnostic tool, not a cure. It is a prison guard, not a liberator. Its purpose was to hold Israel in custody until the Messiah came, and its purpose in the life of a sinner today is to hold him in the custody of his own conscience until he cries out for mercy.
The Judaizers wanted to drag the Galatians back into the prison from which Christ had set them free. They wanted them to relate to God on the basis of their own performance, their own law-keeping. But the law's only verdict for sinners is "guilty." It can do nothing else. It cannot give life. It cannot give righteousness. It can only condemn.
But praise God, that is not the end of the story. The law shuts us up, yes, but it shuts us up so that the promise might be given. And what is that promise? It is the promise of a righteousness that is not our own. It is the promise of a life that is found outside of ourselves. It is the promise of forgiveness and acceptance, given freely to all who stop trying to earn it and simply receive it by faith. It is the promise of Jesus Christ. He is the one who fulfilled the law perfectly on our behalf. He is the one who took the law's curse upon Himself. And He is the one who now offers His perfect record to anyone who will believe. The law drives us to the end of ourselves, so that we might come to the beginning of Christ.