Комментарий к Берешит 21:21

מארץ מצרים FROM THE LAND OF EGYPT — from the place where she was brought up — as it is said (16:1) “And she (Sarah) had an Egyptian handmaid [whose name was Hagar]”. That is what the popular proverb says: “Throw a stick into the air and it will fall back to (literally, stand on) its element” (Genesis Rabbah 53:15).

במדבר פארן, as predicted in 16,12 והוא יהיה פרא אדם.

וישב...ותקח לו אמו, she took a wife for him from her own family, seeing that he had become separated from his father’s family. It is proper for people to marry into members of their family (not too close) as a stronger bond of mutual love is liable to be forged between men and women of similar backgrounds, such as both being members of the same clan