Since contemporary Jewish exegesis of the Hagar-Sarah story would have supported the position of the false teachers in Galatia, it was necessary for Paul to redefine the terms of the story so that he could draw out its real meaning as he saw it. The purpose of his allegorical comparisons is to establish the identification of the false teachers with Hagar and Ishmael (vv. 24-25) and the identification of the Galatian believers with Sarah and Isaac (vv. 26-28).
The identification of the false teachers with Hagar and Ishmael is developed in four steps. The first step identifies Hagar with the covenant from Mount Sinai and the children of Hagar with the children of the Sinaitic covenant: the women represent two covenants. One covenant is from Mount Sinai and bears children who are to be slaves: This is Hagar (v. 24). This comparison is based on the common understanding that the children of slave women are slaves. If Hagar represents the covenant from Mount Sinai, then the children of that covenant are destined to be slaves, since the children of Hagar, the slave woman, were destined to be slaves. Paul has already argued that those who adhere to the Sinaitic covenant are enslaved by it (3:19—4:10). His allegorical comparison here builds on that argument and leads to the identification of the rival teachers with Hagar's children, so that he can appeal to the Galatian believers in the words of Genesis 21:10 to resist the influence of those teachers.
The second step in this identification process undergirds the Hagar-Sinaitic covenant comparison. Such a comparison contradicts the common Jewish understanding that the Sinaitic covenant was given to the descendants of Isaac and was therefore not related to Hagar and her descendants. So now Paul sets forth a Hagar-Mount Sinai equation to support his Hagar-Sinaitic covenant equation: Now Hagar stands for Mount Sinai in Arabia (v. 25). Paul appears to be connecting Hagar with Mount Sinai on the basis of her name and the geographical location of Mount Sinai. In what way the name Hagar can be connected with Mount Sinai is extremely difficult to understand. There may have been some Jewish way of equating the numerical value of the words Hagar and Sinai or the sound of the Hebrew name Hagar may have been similar to the sound of a word associated with Mount Sinai. It is easier to understand how Hagar could be connected with Mount Sinai on a geographical basis, since Mount Sinai is in Arabia, the land inhabited by the Arabians, the descendants of Hagar and Ishmael.
The third step in Paul's identification of the children of Hagar as the false teachers in Galatia is his assertion that Mount Sinai corresponds to the present city of Jerusalem (v. 25). Paul's addition of Jerusalem to his allegorical equations makes sense only if the false teachers themselves were closely identified with the Jerusalem church. In other words, Paul mentions Jerusalem to increase the number of contact points between the false teachers who were associated with Jerusalem and the descendants of Hagar. Perhaps Paul's declaration in the next verse—but the Jerusalem that is above is free, and she is our mother—was his response to one of the slogans of the false teachers: "We come from the mother church in Jerusalem" (Lincoln 1981:17).
The fourth step supports the "Mount Sinai Jerusalem" equation by drawing attention to the common characteristic of slavery of both the children of the Sinaitic covenant and the children of Jerusalem: because she is in slavery with her children. Jerusalem was the proud capital city for all the recipients of the covenant given at Mount Sinai. And the center of life in Jerusalem was the study and teaching of that covenant. The goal of life in Jerusalem was to regulate all of life by the law given at Mount Sinai. Since the Sinaitic covenant enslaved all who relied upon it and tried to regulate their lives by it (see 3:19—4:11), it followed that Mount Sinai and Jerusalem could be equated on the basis of this common characteristic of slavery. Furthermore, since the false teachers were characterized by their emphasis on the demands of the Sinaitic covenant and their appeal to the authority of the Jerusalem church, it follows that they were themselves in slavery and could therefore be identified as the children of Hagar, the slave woman.
Paul's allegorical comparisons are not easy to follow. They have raised a host of unresolved problems for interpreters. But we need to remember that whatever rationale Paul used for his equations of Hagar with Mount Sinai and the present Jerusalem, the goal of these comparisons was the identification of the false teachers with Ishmael as the children of slavery because of their emphasis on the Sinaitic covenant. Once this identification was established, Paul could then appeal to the Galatians in the words of the law itself to get rid of the slave woman and her son.
The identification of the Galatian believers with the children of Sarah begins with a contrast between the present Jerusalem, whose children are in slavery, and the Jerusalem above, which is free. She is our mother, Paul declares (v. 26). This contrast mixes two pairs of opposites: present-future, below-above. In Jewish prophecy the Jerusalem above was the consummation of all of God's promises for his people. In the heavenly new Jerusalem the people of God would experience the perfect rule of God in peace and harmony with him, one another and all of the new creation. But Paul does not put the heavenly Jerusalem in the future. His use of present tense indicates that the Galatian believers are already citizens of the heavenly Jerusalem. Since they are already experiencing the Spirit of God, they are already enjoying the fulfillment of the promises of God. This means that they have already entered the heavenly Jerusalem. They can shout with joy, She is our mother!
This contrast is a dramatic way to show how foolish it would be to follow the demands of the false teachers. They were commending themselves as representatives of Jerusalem and teachers of the law of Moses. But there was no good reason for those who were experiencing the freedom of life as citizens of the heavenly Jerusalem to be bound by slavery to the law, which was characteristic of the present, earthly Jerusalem.
The Jewish pride in Jerusalem is an understandable human affection. We often take special pride in the city of our origin. I'm quite happy to identify myself as a "Chicago boy," since I was born in Chicago. Chicago is one of the great cities of the world, I think. But like Christian in John Bunyan's Pilgrim's Progress, we look forward to the city of our destination, the heavenly Jerusalem. And even now, as Paul insists here, we can rejoice that we are citizens of the heavenly Jerusalem by faith in Christ. One of the greatest reasons for taking delight in our citizenship in the heavenly Jerusalem is that people from every race, nation, language group and social class belong to that city. Whereas identification with the city of our origin sets us apart from people from other cities, identification with our city of destination unites us with people from every city.