And Abram said, behold, to me thou hast given no seed
He had bestowed many temporal blessings on him, as well as spiritual ones, having given himself in covenant, and all things in it, but he had not given him a child:
and lo, one born in my house is mine heir;
meaning either Eliezer or his son, whom he had made his heir, or intended to make him, since he had no child; or of course he would have been to, Lot his nephew having no sons; and this Eliezer descending from Aram, the youngest son of Shem, was like to be next heir, if Abram should have no child of his own, as Dr. Lightfoot observes F7.
F7 Works, vol. 1. p. 695.