Verse 7 But, In Isaac, &c. The general argument commenced here, and coming to its result in Romans 9:18, is this,--that as God, in constituting the Hebrew nation in ancient times, made a selection, for reasons not revealed, of some of the descendants of the patriarchs to the exclusion of others, so does he now choose from among mankind whomsoever he will as objects of spiritual mercy. This first illustration is taken from the case of Isaac, who was chosen to the exclusion of Ishmael, (Genesis 17:19-21,) and of Abraham's six sons, whose mother was Keturah. (Genesis 25:1,2.)