Galatians 4:27

For it is written, Rejoice thou barren that bearest not; Break forth and cry, thou that travailest not: For more are the children of the desolate than of her that hath the husband.

This is quoted from Isaiah 54:1, the application being to Sarah and Hagar, as follows: Sarah at first had no child, but when the promise of Isaac was fulfilled, her posterity exceeded that of Hagar; but in the instance of the spiritual fulfillment of this, the numberless "Sons of Sarah" in the church of the living God even more overwhelmingly outnumber those of Hagar.