These are the sons of Ishmael, and these are their names, by their towns,—unwalled encampments, from hatzar, to surround; used of the movable villages of nomadic tribes (cf. Isaiah 42:11)—and by their castles;—fortified keeps (Murphy); tent villages (Keil); nomadic camps (Kalisch). Cf. Numbers 31:10; 1 Chronicles 6:39; Psalms 69:26; Ezekiel 25:4)—twelve princes—this does not imply that Ishmael had only twelve sons, like Israel—a very suspicious circumstance (De Wette); but only that these twelve became phylarchs (Havernick). The Egyptian dedecarchy rested on a like earlier division of names. Homer mentions a similar case among the Phoenicians; Thucydides another in ancient Attica (2. 15); vide Havernick's 'Introch,' § 18—according to their nations (or tribe divisions).
And these are the years of the life of Ishmael, an hundred and thirty and seven years:—a life shorter by nearly half a century than that of Isaac (Genesis 35:21); does this prove the life-prolonging influence of piety?—and he gave up the ghost and died; and wee gathered unto his people (vide on Genesis 25:8). And they dwelt from Havilah unto Shur, that is before Egypt, as thou goest toward; Assyria (vide Genesis 10:29; Genesis 16:7): and He died—literally, fell down; not expired (Vulgate, A Lapide, Aben Ezra, et alii), but settled down, had his lot cast (Calvin, Keil, Kalisch); κατῴκησε (LXX.) in the presence of all his brethren (a fulfillment of Genesis 16:12).
HOMILETICS