The “brothers” with which Paul opens this section of his letter contrasts with the “O foolish Galatians” with which he introduced the chapter. It indicates a change of tone on Paul’s part and reminds his readers, both the Galatians and us, of their common relationship to Jesus Christ (“he [is] the firstborn among many brothers,” Romans 8:29, ESV; all Biblical quotations are from the ESV) and the fraternal attitude that they should have towards one another.
The Priority of the Promise
15 To give a human example, brothers: even with a man-made covenant, no one annuls it or adds to it once it has been ratified. 16 Now the promises were made to Abraham and to his offspring. It does not say, “And to offsprings,” referring to many, but referring to one, “And to your offspring,” who is Christ. 17 This is what I mean: the law, which came 430 years afterward, does not annul a covenant previously ratified by God, so as to make the promise void. 18 For if the inheritance comes by the law, it no longer comes by promise; but God gave it to Abraham by a promise.
In verses 6 to 9 and 14, Paul connected justification by faith with God’s promise to Abraham, “[I]n you all the families of the earth shall be blessed” (Genesis 12:3). Now he shows the priority of that promise over the law, claiming that since God had ratified an earlier covenant , it couldn’t be set aside or changed by a covenant made over four centuries later. (The Greek word translated “covenant” in the passage, diatheke, usually means “will” or “testament” but was used by the LXX for the standard Hebrew word for “covenant.” Commentators disagree on whether Paul meant “covenant” or “will/testament” or a mix of their meanings.) But that is what would happen if the teachings of the Judaizers–Jewish Christians who told Gentile Christians that they had to be circumcised and obey the Mosaic law, in addition to believing in Jesus Christ, to be saved–was accepted.
Paul also observes that God made the promise to Abraham and his “offspring” (Genesis 12:7; 13:15; 17:7; 24:7) and argues that since “offspring” is singular and not plural the promise was to be inherited by one person, Christ, rather than by many people, the Jews, as the Judaizers claimed. (Paul’s argument has been criticized because in both Hebrew and Greek, as in English, the singular “offspring” has a collective sense. On the other hand, the principle of selecting one offspring to receive the promise out of many possible offspring was established early in Israel’s history when God distinguished between Isaac and Ishmael as the offspring of Abraham [Genesis 24:7].) In view of Paul’s use of “offspring” elsewhere (for example, in Galatians 3:29, “And if you are Christ’s, then you are Abraham’s offspring, heirs according to promise”), he is probably thinking of Christ as head of a spiritual race rather than as an individual.
The Purpose of the Law
Since according to Paul the law was given after God’s promise to Abraham and had no effect on it, the question of why God gave the law arises. Paul now considers that question and gives the following reasons:
1. The law was “added because of transgressions” (3:19-20).
2. The law was given to convince people of their need for a Saviour (3:21-22).
3. The law was intended to be “our guardian until Christ came” (3:23-25).
1. The law was “added because of transgressions.”
19 Why then the law? It was added because of transgressions, until the offspring should come to whom the promise had been made, and it was put in place through angels by an intermediary. 20 Now an intermediary implies more than one, but God is one.
The law wasn’t added to change or annul God’s promise to Abraham but because of transgressions. What does Paul mean by “because of transgressions”? The average reader naturally thinks of it as meaning “to restrain sins,” restraining transgressions being the basic function of law, but most commentators interpret the phrase in light of what Paul wrote to the Romans–“through the law comes knowledge of sin” (3:20) and “the law came in to increase the trespass” (5:20)–as meaning “to reveal sin” or even “to provoke sin.”
Angels are referred to in connection with the giving of the law in Deuteronomy 33:2, “The LORD came from Sinai and dawned from Seir upon us; he shone forth from Mount Paran; he came from the ten thousands of holy ones.” The intermediary by whose hand the law was given was Moses, who told the Israelites, “I stood between the LORD and you at that time, to declare to you the word of the LORD. For you were afraid because of the fire, and you did not go up into the mountain” (Deuteronomy 5:5).
Numerous explanations have been made of verse 20. The basic idea seems to be that the law was inferior to the promise because the law was mediated but the promise was given directly. The law’s inferiority to the promise is also indicated in this passage by its temporal nature, “added…until the offspring should come.”
2. The law was given to convince people of their need for a Saviour.
21 Is the law then contrary to the promises of God? Certainly not! For if a law had been given that could give life, then righteousness would indeed be by the law. 22 But the Scripture imprisoned everything under sin, so that the promise by faith in Jesus Christ might be given to those who believe.
The law’s being so different from the promise suggests that it might be opposed to the promise. To that suggestion Paul responds emphatically, “Certainly not!” He then goes on to state his reason, negatively in verse 21b and positively in verse 22. The law was never intended to make alive or reckon righteous. Rather it confined everybody under sin so that “the promise by faith in Jesus Christ might be given to those who believe” (compare Romans 11:31, “God has consigned all to disobedience, that he may have mercy on all”). (Actually, Paul attributes the confining to “the Scripture.” Commentators disagree on whether “the Scripture” refers to the Scriptures in general, such as those cited in Romans 3:10-18, or to a particular passage that Paul has already cited. Particular passages that have been proposed are Psalm 143:2, possibly alluded to in Galatians 2:16, and Deuteronomy 27:26, quoted in Galatians 3:10.)
3. The law was intended to be “our guardian until Christ came.”
23 Now before faith came, we were held captive under the law, imprisoned until the coming faith would be revealed. 24 So then, the law was our guardian until Christ came, in order that we might be justified by faith. 25 But now that faith has come, we are no longer under a guardian.
It’s tempting to relate this passage to one’s personal experience of abandoning his or her attempt to establish righteousness by works of the law and of accepting the righteousness which comes by faith in Jesus Christ. However, most modern commentators relate the passage to the change from the age of law to the age of faith that was inaugurated by the coming of Jesus Christ and fulfilled the promise to Abraham. Thus that is how I shall take it here.
“[W]e were held captive under the law, imprisoned” is remarkably parallel to verse 22. However, while verse 22 refers to “everything” being imprisoned, verses 23-25 seem to refer specifically to the Jews (“we”). Also, here the law, instead of sin, is the jailer, suggesting that to be “under the law” is in practice to be “under sin.” Compare Romans 6:14, “For sin will have no dominion over you, since you are not under law but under grace.” The reason is that, although forbidding sin, the law stimulates it (Romans 5:20, quoted above).
A “guardian” or paidagogos was a person, usually a slave, charged with the conducting of a child to and from school, seeing that he didn’t fall into harm or get into mischief, and drilling him on what he had learned. Similarly the law served God’s purposes by “imprisoning” (guarding and restricting) the Jews.
The law did what it was intended to do. Then Jesus Christ came and the law was no longer needed. The Judaizers failed to realize this and told the Galatian Christians that they had to follow the law, in addition to believing in Jesus Christ, to be saved. Are you still trying to mix law and grace, as the Judaizers did, or are you trusting completely in what Jesus Christ did for our salvation?