Jamieson, Fausset and Brown on Genesis 21:14

Ge 21:14-21. Expulsion of Ishmael.

14. Abraham rose up early, &c.--early, that the wanderers might reach an asylum before noon. Bread includes all sorts of victuals--bottle, a leathern vessel, formed of the entire skin of a lamb or kid sewed up, with the legs for handles, usually carried over the shoulder. Ishmael was a lad of seventeen years, and it is quite customary for Arab chiefs to send out their sons at such an age to do for themselves: often with nothing but a few days' provisions in a bag.

wandered in the wilderness of Beer-sheba--in the southern border of Palestine, but out of the common direction, a wide extending desert, where they lost their way.