Matthew Poole and continuators on Galatians 4:27

27 For it is written, Rejoyce thou barren that bearest not, break forth and cry, thou that travailest not, for the desolate hath many mo children, then she which hath an husband .

It is written Isa. 54.1. Some think that the Apostle doth but allude to that of the Prophet, and that the sense of the Prophet was only to comfort the Iews, whose City, though it should be for a present time barren, thin of Inhabitants, during the time of the Babylonish Captivity; yet it should be again replenished with people, and be more populous then other Cities. But the Prophet seemeth rather to interpret that Prophesie, then meerly to allude to it; so that verse is one of those Prophetical passages about the calling of the Gentiles, (of which are many in that Prophet.) In this sense, the Gentiles are to be understood under the notion of the woman that was barren and desolate. The Church of the Iews is represented under the notion of a Woman that had an Husband and Children. The Prophet, by the Spirit of Prophesie, calleth upon the Gentiles, that brought forth no children to God, and to whom God was not an Husband, to Rejoyce, and to cry out for joy, for there should be more Believers, more children brought forth to God, amongst them, then were amongst the Iews: So as the Church of the Gentiles are compared to Sarah, who was a long time barren, but then brought forth the child of the Promise, the Seed in which all the Nations of the Earth were to be blessed.