Charles Ellicott Commentary Genesis 16:2

"And Sarai said unto Abram, Behold now, Jehovah hath restrained me from bearing; go in, I pray thee, unto my handmaid; it may be that I shall obtain children by her. And Abram hearkened to the voice of Sarai." — Genesis 16:2 (ASV)

That I may obtain children by her. —Hebrew, that I may be built by her. The words, ben = a son, bath (originally banth) = a daughter, bayith (banith) = a house, and bânâh = to build, all belong to the same root in Hebrew. The idea is that children build the house and give a man the pledge of continuance. Until late times, the tent was the dwelling, while the house was the family (Genesis 7:1).

Thus, the phrase “to build a man a sure house” meant to give him lasting prosperity (1 Samuel 2:35). Hence also, the close connection between building and the bestowal of children is found in Psalm 127:0. Since the children of a woman bestowed by her mistress upon the husband were regarded as belonging to the wife (Genesis 30:3), Sarah, despairing of bearing a son herself, as she was now seventy-five and had been ten years in Canaan, concluded that her heir was to be born of a substitute.

Regarding the morality of the act, we find that marriage with one wife was the original law (Genesis 2:24), and that when polygamy was introduced, it was coupled by the inspired narrator with violence and license (Genesis 4:19). Monogamy was the rule, as we see in the households of Noah, Terah, Isaac, and others; but many, like Esau and Jacob, allowed themselves greater latitude.

In doing so, their conduct falls below the standard of Christian morality. However, everyone’s actions are strongly influenced by the general views of the people among whom they live. In Abram’s case, it must be said in his defense that, with so much depending on his having offspring, he took no steps to obtain another wife but remained content with the barren Sarai. When he did take Hagar, it was at his wife’s request and for a reason that seemed to them adequate and even religious.

Rachel subsequently did the same for a much lower motive. The consent of the wife was all-important in such cases; similarly, in ancient India, such consent was necessary to make a second marriage valid (see Wilson’s Hindu Theatre, Vol. 1, p. 179).