Abraham rose up early, &c.— After so express a declaration from God, Abraham delayed not to obey: and though it is certain that God directed his conduct in this whole transaction, yet he has not escaped the charge of cruelty; in answer to which it must be remarked, that though the ambiguity of our English translation, which seems to intimate that Hagar took the child upon her shoulder, and afterwards, Genesis 21:15 that she cast the child under one of the shrubs, represents Hagar's circumstances as very calamitous; yet they were far from being so distressful as this representation seems to make them: for, 1st, Ishmael was not an infant at this time, but at least fifteen or sixteen (Le Clerc says seventeen) years old; for at the birth of Isaac he was fourteen. Compare chap. Genesis 16:16. with ch. Genesis 21:5. And if Isaac were two years old when Sarah weaned him, Ishmael must at least have been sixteen, when Abraham sent away him and his mother. Hagar therefore had not a child to provide for, but a youth capable of being a comfort and assistant to her. 2nd, It was easy then for any person to find a sufficient livelihood in the world: those who had flocks found ground enough to spare in every country to maintain them; and the creatures of the world were so numerous, that a person who had no flocks might, in the wildernesses and uncultivated grounds, kill enough of all sorts for maintenance, without injuring any one: and thus Ishmael dwelt in the wilderness, and became an archer, Genesis 21:20. Neither are we to imagine that this wilderness was quite an uncultivated desart, for there were houses, and even cities, or villages, scattered up and down in it; but it is called a wilderness, as being a mountainous tract, and less inhabited than other parts of the country. Thus, if other means failed them, they might let themselves for hire to those who had flocks and herds of sheep and cattle, and find, perhaps, as easy a maintenance in their service as Hagar and Ishmael had even with Abraham.
Accordingly, it appears that Hagar met with no great difficulty in providing for herself or her son. In a few years she saw him in so comfortable a way of life, as to get him a wife out of another country to come and live with him, Genesis 21:21. 3rdly, Ishmael, and consequently Hagar, fared no worse than the younger children used to fare in those days, when they were dismissed in order to their settling in the world. We mistake therefore in imagining that Hagar and Ishmael were such sufferers in Abraham's dismissing them. At first it might, perhaps, be disputed, whether Ishmael the firstborn, or Isaac the son of his wife, should be Abraham's heir; but after this point was determined, provision was to be made, that Ishmael should either go and plant a family of his own, or he must have been Isaac's servant, if he had continued in Abraham's family. Read the history of Jacob's journey, ch. 28: and 29: The bread and water which Abraham gave Hagar includes all sorts of provision for their present necessity, till they came to the place to which Abraham in all probability directed them to bend their course.
She departed, and wandered in the wilderness of Beer-sheba— Hagar, departing from the place of Abraham's abode, lost her way, as appears from the text, and wandered, so lost, in that wilderness, which was afterwards called Beer-sheba; see Genesis 21:31. This occasioned her distress, especially her want of water, which frequently was rare to be found in desarts of this kind: a distress, it is to be observed, merely accidental, if this interpretation be allowed. Her son, wearied and fainting for want of water to allay his thirst, was unable to proceed farther; she laid him down therefore, Genesis 21:15. (not cast him, as in our translation) under one of the shrubs; and expecting nothing less than his death, as she saw no possibility of relieving his or her own wants, she sat down at a distance from him, not able to endure the miserable prospect of his departure. Her situation was truly pitiable; and the heart cannot but feel for the unhappy mother weeping for her son. It is most probable that Abraham directed Hagar to go down into the land of AEgypt.