John Gill Commentary Genesis 25:16

"These are the sons of Ishmael, and these are their names, by their villages, and by their encampments. Twelve princes according to their nations." — Genesis 25:16 (ASV)

These [are] the sons of Ishmael The twelve before mentioned, (Genesis 25:13–15) : 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.