Matthew Poole and continuators on Genesis 21:15

15 And the water was spent in the bottle, and she cast the child under one of the shrubs.

Not as if she carried him in her arms or upon her shoulders, for he was now about eighteen year old, but being weak and faint and no doubt much dejected in spirit upon the prospect of his desolate and distressed condition, she was forced to support and lead him by the hand, but now, despairing of his life, she lays him down under a shrub.