The Book of Galatians: Chapter 4 (verses 4:21–5:1)

November 7, 2023

by Peter Amsterdam

The Apostle Paul continues to exhort his readers to live in freedom from the Old Testament law. He tries to help the Galatians to see the folly of reverting to the law, and reminds his readers that those who trust in God’s promise (rather than the law) have great hope, as they put their trust in the work of the Holy Spirit.

Tell me, you who desire to be under the law, do you not listen to the law?1

Some of the Galatian believers wanted “to be under the law.” Besides expecting believers to undergo circumcision, they also were attempting to keep the whole law, which was signified by their adherence to the Old Testament calendar. Those who put themselves under the law were living in the old era of the Mosaic law. Therefore, Paul says that they should listen to what the “law,” the Old Testament, says.

In the following verses, Paul tries to explain that living under the law is not according to what Scripture teaches. Those who lived under the Mosaic law lived in bondage to sin. Freedom from that bondage has come through the proclamation of the gospel.

For it is written that Abraham had two sons, one by a slave woman and one by a free woman.2

Paul refers to the Old Testament, though he doesn’t give specific verses. Abraham has already been mentioned in this letter, and now Paul looks to Abraham’s role as the father of two sons, Ishmael and Isaac, who were born of two women, Hagar and Sarah. Hagar, the mother of Ishmael, was a slave; and Sarah, the mother of Isaac, was free.

But the son of the slave was born according to the flesh, while the son of the free woman was born through promise.3

Rather than using the two women’s names, Paul continued to refer to them as slave and free. His focus is rather on the birth of the two sons. The son of Hagar (Ishmael), the slave woman, was born through the natural process of birth, while Sarah’s son (Isaac) was born according to God’s promise. Abraham and Sarah’s attempt to have a child through Hagar was a lack of faith on their part; they made a human attempt to fulfill the promise of God.

The birth of Isaac couldn’t be credited to human effort. The promise that Abraham and Sarah would have a son was so surprising that Abraham laughed in disbelief when he heard it. Then Abraham fell on his face and laughed and said to himself, “Shall a child be born to a man who is a hundred years old? Shall Sarah, who is ninety years old, bear a child?”4 Abraham tried to convince the Lord that Isaac wasn’t needed, as Ishmael could fulfill the promise. Abraham’s suggestion was rejected, and God declared that the covenant would be through Isaac, not Ishmael. Ishmael would receive other blessings as Abraham’s son.

The Judaizers most likely saw themselves as descendants of Isaac. However, Paul sees them as descendants of Ishmael, and sees the Galatian believers as sons of Isaac. Those who rely on the law and human effort to be in good standing with God are not the children of the covenant. Rather it is those who rely on the promises in Christ who are the true children of the covenant.

Now this may be interpreted allegorically: these women are two covenants. One is from Mount Sinai, bearing children for slavery; she is Hagar.5

The word allegorically only occurs this one time in Scripture. An allegory is a piece of writing that contains a hidden moral or political meaning. Paul’s language indicates that he is about to engage in an allegorical reading. Such reading was an established tradition of reading texts, especially “sacred” or “canonical” text, in the ancient world where an element signifying one thing literally is taken to mean something else. So, “these women are two covenants” fits this mode of writing.

In this allegory, the women represent two covenants, which are quite different from one another. The one from Mount Sinai (the Sinai covenant) is represented by Hagar. This covenant was established with Moses and Israel. Even though Israel’s freedom from Egypt was celebrated in Sinai, Paul associates slavery with Sinai. The Galatian readers of Paul’s letter would not have been surprised, since Paul made the point throughout Galatians that the law does not free from sin but rather enslaves. The law, as part of the old covenant, doesn’t free the people of God from sin.

Now Hagar is Mount Sinai in Arabia; she corresponds to the present Jerusalem, for she is in slavery with her children.6

Paul sees a correspondence between Hagar and Mount Sinai, and draws a connection between Hagar and the Jerusalem of his day, as he sees the Jews as enslaved under the law. The Judaizers wanted to impose the Old Testament law on the Gentile converts, and this required Gentiles to be circumcised in order to be converts. Paul emphasized the theme of slavery, and said that Jerusalem, along with her children, is enslaved. While the standard Jewish view was that the law was the pathway to freedom, Paul pointed out that it ends up enslaving people. The law demands obedience but does not give people any power to keep its principles.

But the Jerusalem above is free, and she is our mother.7

Paul contrasts the earthly Jerusalem with the Jerusalem above (heaven). The Jerusalem above is free, and it is this Jerusalem that is the mother of believers in Christ. Believers are the inhabitants of the heavenly Jerusalem.

Elsewhere in the New Testament, the heavenly Jerusalem represents heaven, which awaits believers. According to Paul, the Jerusalem above has reached down into the present evil age. Even though the heavenly Jerusalem hadn’t arrived in its fullness, the age to come had invaded the present evil age. As Sarah was the mother of Isaac, so the believers are part of the new age of the Spirit. They aren’t slaves like the Judaizers, but are free sons due to the Spirit’s work.

For it is written, “Rejoice, O barren one who does not bear; break forth and cry aloud, you who are not in labor! For the children of the desolate one will be more than those of the one who has a husband.”8

Paul quotes from Isaiah 54:1 to support what he wrote in Galatians 4:27. He makes the point that the Gentile Christians in Galatia are the children of the Jerusalem above. For they are the children of the barren woman from whom no children were expected. But miraculously, they have new life.

The connection between the verse in Isaiah and previous verses is Sarah’s barrenness. Her inability to bear children hampers the promise that Abraham would have offspring. We read of this same situation in the lives of Isaac and Rebekah (Genesis 25:21) and with Jacob and Rachel (Genesis 30:1).

Paul sees the fulfillment of this “covenant of peace” in his day. The return from exile has come in the message of Jesus. The fulfillment of this promise has become a reality in the conversion of Gentile Christians in places like Galatia. The Gentile believers in Galatia are part of the fulfillment of the promise; they are true children of the Lord.

Now you, brothers, like Isaac, are children of promise.9

Paul now starts to explain the meaning of his allegory. The Judaizers see the Galatians as not being true Christians unless they are circumcised. Paul tells them that the Galatian Christians are like Isaac, and they are the true sons of Sarah. They are those who have received the promise, for they are God’s children by virtue of the work of the Holy Spirit.

But just as at that time he who was born according to the flesh persecuted him who was born according to the Spirit, so also it is now.10

Like Ishmael persecuted Isaac, the Judaizers were persecuting those who had been filled with God’s Spirit in Galatia. If the Galatians were Sarah’s true children, then what were the Judaizers who came to Galatia and insisted that believers must be circumcised? While they saw themselves as the sons of Sarah and Abraham, Paul compared them to Ishmael, who ridiculed and persecuted Isaac.11

The Judaizers’ insistence on circumcision didn’t reflect the work of God’s Spirit bringing the Gentiles into the body of believers. Rather the work of the Judaizers in Galatia was persecution. The Galatian Christians are part of the age to come. They have the Jerusalem above as their mother and are filled with God’s Spirit. As such, they must resist the smooth talking of the Judaizers, who seek to bring the slavery of the law and circumcision to the believers.

But what does the Scripture say? “Cast out the slave woman and her son, for the son of the slave woman shall not inherit with the son of the free woman.”12

The Galatians were called to listen to the story of Isaac and Ishmael, as it spoke to their situation. It informed them that those who belonged to the slave woman wouldn’t receive the inheritance.

When Ishmael ridiculed Isaac, Sarah, the mother of Isaac, saw Ishmael as a rival to her son. Thus, she demanded that Abraham remove Ishmael and his mother, Hagar, from the household, as the inheritance belonged only to Isaac.13 Abraham hesitated to do what Sarah demanded, as he loved his son Ishmael.14 God instructed Abraham to carry out Sarah’s request.15 The inheritance was through Isaac, not Ishmael. Only Isaac was the son of promise.

In the Old Testament, we see that those who are sons of the slave woman will not receive the inheritance. Paul is reminding his readers that those who put themselves under the Sinai covenant won’t receive the inheritance. The Galatians are encouraged to stay in the sphere of the promise, as only those who are children of Sarah will receive the inheritance.

So, brothers, we are not children of the slave but of the free woman.16

Paul restates the conclusion that he made earlier when he wrote: Now you, brothers, like Isaac, are children of promise.17 Since the Galatians were born of the Spirit instead of the flesh, they were children of Jerusalem above rather than of Hagar, and therefore children of the promise. Therefore they are children of the free woman and belong to the heavenly rather than the earthly Jerusalem.

For freedom Christ has set us free; stand firm therefore, and do not submit again to a yoke of slavery.18

This is the first verse of Galatians 5. While it is part of chapter 5, the context connects it to chapter 4. The purpose of Christ’s work is summed up in this short statement: Jesus freed His people so that they could enjoy the freedom of the gospel.

Freedom versus slavery has been the focus of verses 4:21–31. This verse, Galatians 5:1, provides a transition between the last verses in chapter 4 and the early verses of chapter 5.

For the Galatians to yield to circumcision is to return to the Mosaic law. It’s a return to the Sinai covenant, which is one of slavery. In doing so, they will put themselves into Ishmael’s family rather than Isaac’s. Paul stresses that they must continue in freedom from the law, which was what they did when they first became believers. Since the Galatians are free from the law through Christ, they need to stand fast in that freedom.

Paul concludes with the main point. The Galatians must stand strong in their freedom. They should resist the pressure to submit to circumcision and the law. They belong to the Jerusalem above (heaven) and to the free woman (Sarah). They are inheritors of the promises and have received the Holy Spirit. They are to enjoy and live in the freedom that is theirs through Christ.


Unless otherwise indicated, all scriptures are from the Holy Bible, English Standard Version, copyright © 2001 by Crossway Bibles, a division of Good News Publishers. Used by permission. All rights reserved.

1Galatians 4:21.

2 Galatians 4:22.

3 Galatians 4:23.

4 Genesis 17:15–21.

5 Galatians 4:24.

6 Galatians 4:25.

7 Galatians 4:26.

8 Galatians 4:27.

9 Galatians 4:28.

10 Galatians 4:29.

11 Genesis 21:9–10.

12 Galatians 4:30.

13 Genesis 21:10.

14 Genesis 21:11.

15 Genesis 21:12.

16 Galatians 4:31.

17 Galatians 4:28.

18 Galatians 5:1.