Adam Clarke on Genesis 17:16

I will bless her, etc. - Sarah certainly stands at the head of all the women of the Old Testament, on account of her extraordinary privileges. I am quite of Calmet's opinion that Sarah was a type of the blessed Virgin. St. Paul considers her a type of the New Testament and heavenly Jerusalem; and as all true believers are considered as the children of Abraham, so all faithful holy women are considered the daughters of Sarah, Gal 4:22, Gal 4:24, Gal 4:26. See also 1Pet 3:6.