Common misconception...
Galatians 4
Galatians 4 ►
English Standard Version
Sons and Heirs
1I mean that the heir, as long as he is a child, is no different from a slave,a though he is the owner of everything, 2but he is under guardians and managers until the date set by his father. 3In the same way we also, when we were children, were enslaved to the elementary principlesb of the world. 4But when the fullness of time had come, God sent forth his Son, born of woman, born under the law, 5to redeem those who were under the law, so that we might receive adoption as sons. 6And because you are sons, God has sent the Spirit of his Son into our hearts, crying, “Abba! Father!” 7So you are no longer a slave, but a son, and if a son, then an heir through God.
21Tell me, you who desire to be under the law, do you not listen to the law? 22For it is written that Abraham had two sons, one by a slave woman and one by a free woman. 23But the son of the slave was born according to the flesh, while the son of the free woman was born through promise. 24Now this may be interpreted allegorically: these women are two covenants. One is from Mount Sinai, bearing children for slavery; she is Hagar. 25Now Hagar is Mount Sinai in Arabia;e she corresponds to the present Jerusalem, for she is in slavery with her children. 26But the Jerusalem above is free, and she is our mother. 27For 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.”
28Now you, brothers, like Isaac, are children of promise. 29But 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. 30But 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.” 31So, brothers, we are not children of the slave but of the free woman.
Still don't get ya.
Here is what my NKJV bible study says
Once again Paul speaks of the law and the experience of Abraham, addressing the false teachers’ foundational respect for Abraham (3:6–9) and the Galatians’ infatuation with living under the law. To clinch his lengthy argument about the bondage of the law and the freedom found in Christ, Paul uses as examples the two sons of Abraham. These are Ishmael, who was born of the bondwoman Hagar (v. 24); and Isaac, who was born of Sarah, the rightful wife of Abraham and a freewoman. Appropriately, Paul counters the Jewish false teachers’ zeal for the law with an argument based on the Law, the Pentateuch (Gen. 16:15; 21:2). He uses allegory to prove his point because it was a rhetorical technique the false teachers used. In other words, Paul was demonstrating that he could argue from the Law just as well as they could, but to prove that the Law of Moses pointed to the Messiah, Jesus Christ.
4:23 In Gen. 16, Abraham and Sarah attempted to fulfill God’s promise through their own strength, using Hagar, a bondwoman. In spite of the complications caused by that “fleshly” alternative, Sarah, a freewoman, eventually saw the miraculous outworking of God’s promise in the birth of Isaac (see Gen. 12:2; 15:4).
4:24 symbolic: Paul was using the common Jewish allegorical method of the day to make his point. He used this approach to draw a stark contrast between two biblical covenants at odds with each other in the churches in Galatia: the Abrahamic promise (see Gen. 12:1–3) and the Law of Moses that God gave Israel at Mount Sinai.
4:25 Paul compared Jerusalem, the center of Jewish life, to Mount Sinai, the birthplace of the Law of Moses.
4:26 The Jerusalem above represents the Jewish hope of heaven finally coming to earth (see Rev. 21; 22). Since us all obviously refers to those who are free through faith in Christ (v. 7), Paul was strongly implying that the question at hand was not allegiance to Jerusalem, but allegiance to which Jerusalem—the new or the old? Would the Galatians follow the shortsighted present Jerusalem and its legalism or the liberty of the heavenly Jerusalem?
4:27 Paul quotes Is. 54:1, using the prophesied restoration of Israel from judgment and exile to illustrate how the later-born children of promise would eventually far outnumber the earlier offspring.
4:28–30 This portion of Paul’s allegory is based on Gen. 21:9, 10. Isaac was continually persecuted by his older half brother Ishmael. Eventually, Ishmael and his mother Hagar were expelled because Ishmael had no standing in God’s eyes as heir of Abraham. In creating a parallel between the story from Genesis and the Galatians’ situation, Paul points out that (1) the persecution by the Jewish legalists of his day was not unexpected, and (2) it would not go on indefinitely because the legalists would soon be cast out.
4:31-5:1 So then represents the conclusion of the previous section, while therefore signals that Paul is going to apply this spiritual truth to the lives of the Galatian believers. To be children of the bondwoman is to be enslaved to the covenant from Mount Sinai (4:24, 25), the Law of Moses. To be of the free is to follow Abraham’s example of faith (3:6–9), to be “born according to the Spirit” (3:2; 4:29), and to be destined for the “Jerusalem above” (4:26). Understanding such realities, the believer in Christ must continually stand fast in the liberty of not having to keep the Law of Moses in order to be saved. The Galatians were on the verge of becoming enslaved to the law again.
I can't see from this how Hagars children were under the old covenant.
To me Paul is saying if you want to stay under the old covenant then you are in effect the children of Hagar (even though Israel were not the children of Hagar) yet if you enter into the new covenant then you are the children of Abraham, that is Christ saves and not the law. This is the faith Abraham had.
Abraham had to separate Ishmael from Isaac; not because Isaac was better than Ishmael, but because of the marriage covenant between Abraham and Sarah. God could bless Ishmael, but the covenant had to be maintained through Isaac.
Abraham and Isaac both made tragic mistakes in giving their wives to other men, which endangered both the seed and the covenant. God had to intervene miraculously to rescue the seed, even at the risk of killing an innocent tribe (Genesis 12:10-20; 20:1-9; 26:7-11).