Galatians 4:21-25 Tell me, you that desire to be under the law, do you not hear the law? For it is written, that Abraham had two sons, the one by a bondmaid, the other by a freewoman. But he who was of the bondwoman was born after the flesh; but he of the freewoman was by promise. Which things are an allegory: for these are the two covenants; the one from the mount Sinai, which gendered to bondage, which is Agar. For this Agar is mount Sinai in Arabia, and answered to Jerusalem which now is, and is in bondage with her children.
‘That Abraham had two sons, the one by a bondmaid, the other by a freewoman.’ Recorded in Genesis 16:15 and 21:1-8. Abraham had six more sons from his second marriage to Keturah (Gen. 25:1-2).
‘After the flesh’ – that is, nothing supernatural in his birth for both parents were normal.
‘By promise’ – both parents were past age and it was impossible in the natural to have Isaac. So, by promise and by the supernatural renewal of youth he was born.
‘Allegory’ – an extended simile; a symbolic representation; natural or religious story, of which the lesson is the substance and the details are but accessories to the main point. The main idea is that Sarah and Hagar symbolize the old and new covenants. Hagar represents the Mosaic law that gendered to bondage and which has been cast out and abolished (4:24-25, 30). Sarah represents the new covenant that gives freedom from bondage and brings men to God, making them children of His by the new birth (4:26-31). The teaching is that the old covenant has been cast out and is no longer in force (4:30; Acts 15:1, 24).
‘Gendered to bondage’ – brings children into slavery to rites and ceremonies that never justify (2:16; 4:9; 5:1; Acts 15:10). This illustrates earthly Jerusalem which is in bondage with her children (4:25).