Paul drew three applications from his interpretation. First, Christians are similar to Isaac in that they experience a supernatural birth and are part of the fulfillment of God"s promise. Therefore they should not live as enslaved sons. [source][source][source]
Context Summary
Galatians 4:21-31 - "children Of Promise"
In this allegory of Sarah and Hagar, it is important to notice that Paul is not dealing with the principle of evil within our hearts, but with the attempt to mingle two dispensations or methods of religious experience-the Law and the Gospel.
He says that the poor slave girl, Hagar, whom Abraham bought as a personal attendant for his wife, stands for Mount Sinai, the mountain of the Law, in the district of Arabia, from which she may have originally come. Hagar also stands for the Judaizers, whose headquarters were at Jerusalem, while their emissaries everywhere dogged the Apostle's movements, insisting that his converts must come under the old Levitical ceremonialism. Paul says that the Galatians must choose between their slavish observance of outward ritual and a simple faith in the finished work of Jesus; and exhorts them to cast out Hagar and Ishmael, which savor of the flesh, and to give themselves to the service of the Spirit, which stands for freedom, peace, and joy in God. Let us also guard against a religious scrupulosity and subservience to the outward, and cultivate a quick sensitiveness to the Holy Spirit. [source]
Chapter Summary: Galatians 4
1We were under the law till Christ came, as the heir is under the guardian till he be of age 5But Christ freed us from the law; 7therefore we are servants no longer to it 14Paul remembers the Galatians' good will to him, and his to them; 22and shows that we are the sons of Abraham by the freewoman
Greek Commentary for Galatians 4:28
Now we [ημεις δε] Some MSS. have υμεις δε humeis de (now ye). In either case Paul means that Christians (Jews and Gentiles) are children of the promise as Isaac was (κατα Ισαακ kata Isaak after the manner of Isaac). [source]
Children of promise [ἐπαγγελίας τέκνα] Not promised children, nor children that have God's promise, but children who are not such by mere fleshly descent, as was Ishmael, but by promise, as was Isaac: children of the Jerusalem above, belonging to it in virtue of God's promise, even as Isaac was the child of Sarah in virtue of God's promise. [source]
Reverse Greek Commentary Search for Galatians 4:28
Romans 2:29Whose praise [ου ο επαινος] The antecedent of the relative ου hou is Ιουδαιος Ioudaios (Jew). Probably (Gifford) a reference to the etymology of Judah (praise) as seen in Galatians 4:28. [source]
What do the individual words in Galatians 4:28 mean?
Greek Commentary for Galatians 4:28
Some MSS. have υμεις δε humeis de (now ye). In either case Paul means that Christians (Jews and Gentiles) are children of the promise as Isaac was (κατα Ισαακ kata Isaak after the manner of Isaac). [source]
Lit. after the manner of Isaac. See Romans 9:7-9, and, for this use of κατὰ , 1 Peter 1:15; Ephesians 4:24; Colossians 3:10. [source]
Not promised children, nor children that have God's promise, but children who are not such by mere fleshly descent, as was Ishmael, but by promise, as was Isaac: children of the Jerusalem above, belonging to it in virtue of God's promise, even as Isaac was the child of Sarah in virtue of God's promise. [source]
Reverse Greek Commentary Search for Galatians 4:28
The antecedent of the relative ου hou is Ιουδαιος Ioudaios (Jew). Probably (Gifford) a reference to the etymology of Judah (praise) as seen in Galatians 4:28. [source]