Genesis 21:15

15. Cast the child From this it has been inferred that Ishmael could not have been a youth of over fifteen years . But neither the word lad ( נער ) (Genesis 21:12) nor child ( ילד ) implies that Ishmael was an infant, nor does the word cast ( שׁלךְ ) necessarily imply that she hurled him from her arms . “The boy was young, but he was old enough to give offence to Sarah by mocking . At a time when human life was much longer than it now is, (Ishmael himself died at 137, Genesis 25:17,) fifteen or sixteen would be little removed from childhood . The growing lad would be easily exhausted with the heat and wandering; whilst the hardy habits of the Egyptian handmaid would enable her to endure much greater fatigue . She had hitherto led the boy by the hand; now she left him, fainting and prostrate, under the shelter of a tree . ” Speaker’s Commentary .