Galatians 4:25–27, “Now Hagar is Mount Sinai in Arabia; she corresponds to the present Jerusalem, for she is in slavery with her children. 26 But the Jerusalem above is free, and she is our mother. 27 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.”
Allegorical interpretation of Scripture is to be rejected because it ultimately strips the text of all meaning. Since allegories can mean something wholly different than what the context allows, there is no way to evaluate different interpretive possibilities. The passage can mean anything, and if it can mean anything, it means nothing and can be misused; however one sees fit.
Paul describes his interpretive work in Galatians 4:21–31 with the same Greek word from which we get the English term allegory (v. 24), but he does not embrace fanciful allegories. Instead, he uses typological interpretation, which, John Calvin writes, is consistent with “the true and literal meaning” of the original text.
Typology is based on the fact that God works in recurring patterns throughout history and says that a past event or person can prefigure or serve as a type of a future person or event. In the antitype, a future person or event more fully expresses the truth of what came before. For example, consider the relation of the exodus to the work of Jesus. God’s rescue of His people from Egyptian bondage typifies the greater salvation from slavery to sin and death He accomplished in Christ. The latter work is consistent with the meaning of the first — in both instances, the Almighty Himself rescues a helpless people. But His work also has a fuller meaning, for a while, people can return to physical slavery, he whom the Son sets free is free indeed, never to be enslaved to evil again (John 8:36).
Typological interpretation can be problematic because too many people call what they are doing typology when they are really employing allegory. Thus, it is generally wise to stick to the typologies explicitly revealed in Scripture.
How do we know that Paul’s reading of the Genesis account is a typology, not an allegory? Remember that Galatians addresses those who attempt to gain the promise of salvation through their own efforts, efforts that enslave people to sin (Gal. 3:10–14). This is precisely what Abraham and the slave-woman Hagar did when they came together to “help God along” and tried to produce the promised heir (Gen. 16:1–6). Paul’s use of Hagar to represent those who try to justify themselves by their deeds is entirely harmonious with the Genesis account.
John Calvin comments, “The true meaning of Scripture is the natural and obvious meaning, and let us embrace and abide by it resolutely. Let us not only neglect as doubtful, but boldly set aside as deadly corruptions, those pretended expositions, which lead us astray from the natural meaning.”