Yes—Paul uses the true historical account of Sarah, Hagar, and their sons as an allegory of the two covenants: law, which brings bondage, and promise, which brings grace.
The Bible says Hagar corresponds to Mount Sinai and gives birth to bondage, while Sarah's son Isaac was born by promise. Les Feldick explains that Paul wrote Galatians because Judaizers were forcing Gentile believers to keep the Law, and the allegory shows that legalism must be cast out, just as Ishmael was cast out of Abraham's household.
Galatians 4:22-31 — This passage contains Paul's full allegory, explicitly connecting Hagar to the covenant from Mount Sinai and Isaac to the child of promise.
Galatians 4:22-25 records Paul's allegory: Abraham had two sons—one by a bondmaid and one by a free woman. He who was of the bondwoman was born after the flesh, while he of the free woman was by promise. Paul explicitly says these things are an allegory, "for these are the two covenants; the one from the mount Sinai, which gendereth to bondage, which is Agar." He then identifies Hagar with Mount Sinai in Arabia and with the Jerusalem that is in bondage. Verse 30 quotes the command, "Cast out the bondwoman and her son: for the son of the bondwoman shall not be heir with the son of the free woman," and verse 31 concludes, "So then, brethren, we are not children of the bondwoman, but of the free."
Les Feldick emphasizes that Paul wrote Galatians under extreme circumstances because Judaizers were telling the Gentile believers in Asia Minor that they could not be saved unless they kept the Jewish Law, circumcision, and all the rest of it—and the believers were falling for it because works always appeals to the human intellect. The allegory in Galatians 4 uses the true history of Abraham's two sons: Ishmael, born after the flesh because it was Sarah's idea, and Isaac, the son of promise whom God gave miraculously after more than twenty years.
Paul had established churches in Asia Minor—present-day Turkey—but word came back that these churches were being besieged by Judaizers who insisted that the believers could not be saved unless they kept the Jewish Law, circumcision, and all the rest of it. The Galatian believers were falling for it, because works always appeals to the human intellect. This is why Paul wrote the whole letter: to prove that these Gentile believers were not under law, but under grace.
Galatians 4:24-25 explicitly says the two covenants are pictured by Hagar and Sarah: Hagar is Mount Sinai in Arabia, which gendereth to bondage. Les identifies the covenant of bondage as the Mosaic Law, and Ishmael as its picture. Hagar, as the bondwoman, is also said to answer to Jerusalem which now is, and is in bondage with her children.
God told Abraham to send Hagar and Ishmael out into the wilderness because Ishmael would not live under the same roof with Isaac, the son of promise. Even earlier, when Hagar was first pregnant, she taunted Sarah and made life miserable for her. Les explains that God did all this because Paul would use it as an allegory: just as Ishmael was sent out, so legalism has to be sent out—you cannot let law and grace live under the same roof.
Isaac was born of the free woman by promise. God had promised Abraham and Sarah a child for more than twenty years, and even when they were past the time of childbearing, God miraculously gave them Isaac. Les teaches that Isaac is indicative of the age of grace—the grace of God based upon all the promises that He would form a plan of redemption. Ishmael stood for law and legalism; Isaac stood for grace and freedom.
The Galatian Crisis
Les explains that Paul wrote Galatians because Judaizers were persuading Gentile believers that they needed circumcision and the Law to be saved, and the believers were falling for it.
Cast Out the Bondwoman
Les says the allegory is why Ishmael had to leave completely—legalism cannot be brought into grace, so the bondwoman and her son must be cast out.
Law vs. Grace Cannot Mix
Les contrasts Ishmael, who stood for law and legalism, with Isaac, who stood for grace and freedom, and stresses that the two could have no interrelationship.
Born of the Flesh vs. Promise
Les explains that Ishmael was born after the flesh because it was Sarah's idea, not God's, while Isaac was born by promise after God miraculously gave him to Abraham and Sarah.
Why Ishmael Was Sent Out
Les shows that God sent Hagar and Ishmael away because Ishmael could not live under the same roof with Isaac, and this is the picture of legalism being sent out.
Hagar Is Mount Sinai
Les identifies Hagar with the covenant from Mount Sinai—the Mosaic Law—which brings bondage, and notes that Sinai is in Arabia.
Old Testament Types for Our Learning
Les says everything in the Old Testament was for our learning, and here Ishmael represents the fleshly law while Isaac represents the age of grace.
God's Providence Behind the Allegory
Les recalls how God sent Hagar back to Sarah's tent and later sent her out into the wilderness, showing God set up the events for Paul's allegory.
Galatians 4:22: For it is written, that Abraham had two sons, the one by a bondmaid, the other by a free woman.
This introduces the historical fact that Paul uses as the basis for the allegory.
Galatians 4:23: But he who was of the bondwoman was born after the flesh: but he of the free woman was by promise.
It draws the line between Ishmael, born after the flesh, and Isaac, born by promise.
Galatians 4:24: Which things are an allegory: for these are the two covenants; the one from the mount Sinai, which gendereth to bondage, which is Agar.
Paul declares the events are an allegory and identifies Hagar with the covenant from Mount Sinai that leads to bondage.
Galatians 4:25: For this Agar is mount Sinai in Arabia, and answereth to Jerusalem which now is, and is in bondage with her children.
Hagar is explicitly equated with Mount Sinai in Arabia and with the present Jerusalem in bondage.
Galatians 4:30: Nevertheless what saith the scripture? Cast out the bondwoman and her son: for the son of the bondwoman shall not be heir with the son of the free woman.
Paul quotes the command to cast out Hagar and Ishmael, showing that legalism cannot share the inheritance with grace.
Galatians 4:31: So then, brethren, we are not children of the bondwoman, but of the free.
The conclusion is that believers belong to the free woman, not to the covenant of bondage.
Les says "we cannot bring legalism into grace." Ishmael stood for law and legalism, while Isaac stood for grace and freedom, and the two could have no interrelationship. Just as Ishmael was sent out of Abraham's household, legalism must be sent out.
Ishmael was born after the flesh because Sarah suggested it, not God. Isaac was born by promise after God promised him for more than twenty years and miraculously gave him to Abraham and Sarah even when they were past childbearing.
God told Abraham to send Hagar and Ishmael into the wilderness because Ishmael would not live under the same roof with Isaac, the son of promise. God did this because Paul would later use the events as an allegory in Galatians 4, showing that legalism cannot coexist with grace.
Watch the Teaching: Abraham, Sarah, and the Allegory of Law vs. Grace | Genesis 20-21