Galatians 4:22

22It has been writtenγέγραπταιforγὰρthatὅτιAbrahamἈβραὰμtwoδύοsonsυἱοὺςhadἔσχεν,oneἕναofἐκtheτῆςslave womanπαιδίσκηςandκαὶoneἕναofἐκtheτῆςfreeἐλευθέρας·

For it has been written that Abraham had two sons, one of the slave woman and one of the free woman.