And Sarai said unto Abram, Behold now, the Lord hath restrained us from bearing. Literally, hath shut me up (i.e. my womb, Genesis 20:18; συνέκλεισέ με, LXX.) from bearing. Her advancing age was rendering this every day more and more apparent.
I pray thee go in unto my maid (cf. Genesis 30:3, Genesis 30:9). It is so far satisfactory that the proposal to make a secondary wife of Hagar did not originate with Abram; though, as Sarai's guilt in making it cannot altogether.
be excused, so neither can Abram be entirely freed from fault in yielding to her solicitations. It may be that I may obtain children by her. Literally, be built up by her; from banah, to build, whence ben, a son (Deuteronomy 25:9; Ruth 4:11).
Calvin notes that Sarai's desire of offspring was not prompted by natural impulse, but by the zeal of faith which made her wish to secure the promised benediction. As yet it had not been clearly intimated that Sarai was to be the mother of Abram's child; and hence her recourse to what was a prevalent practice of the times, while unjustifiable in itself, was a signal proof of her humility, of her devotion to her husband, and perhaps also of her faith in God.
And Abram hearkened to the voice of Sarai. "The faith of both was defective; not indeed with regard to the substance of the premise, but with regard to the method in which they proceeded" (Calvin).