These [are] the sons of Ishmael,.... The twelve before mentioned, Genesis 25:13:
these [are] their names, by their towns and by their castles; their towns and their castles being called after their names, some of which we are able to trace at this distance, as the above notes show:
twelve princes according to their nations; these were princes, or heads of tribes, and there were twelve of them, and continued so, see
Genesis 17:20; where is the prophecy, and here an accomplishment of it.