I have added two paragraphs to my study on the woman of Revelation 12, as follows:
The woman is evidently the same "woman" spoken of in Isaiah 54:1. This "woman" is identified by Paul in Galatians 4:21-31 as the covenant represented by Sarah. This is the same covenant that was confirmed by God 430 years before the Law Covenant had been given. The Law Covenant, represented by Hagar, produced many children while the Abrahamic covenant, represented by Sarah, remained barren.
Galatians 4:25 reveals that Hagar corresponds to the Jerusalem that then existed, who was in bondage with her children. Galatians 4:26 speaks of another Jerusalem, which would correspond with Sarah, representing the Abrahamic covenant that came 430 years before the Law Covenant, and is thus above the Law Covenant. This Jerusalem -- the Abrahamic Covenant -- is the mother of those who belong to Christ.