But God said to Abraham: But introduces the contrast between what Abraham feels and God’s instructions concerning Ishmael.

Be not displeased because of the lad: that is, “Don’t be upset about the boy [Ishmael].” Displeased translates the same verb and idiom as used in verse 11. Lad translates a Hebrew word that may refer to a boy of any age right up to the time of marriage and beyond. In Genesis 22.5 it is also used of Isaac, who carries the wood for the sacrifice; of Joseph (aged 17) in 37.2; of Benjamin in 43.8; 44.22-23. In Gen 14.24 Abraham uses the term to refer to the trained men who fought with him to recapture Lot and his people. Although the word is used to refer to the baby Moses in Exo 2.6, it is also applied by David to the mature Absalom in 2 Sam 14.21. It is apparent that the word is applied to males of a wide range of ages, and the meaning of each occurrence must be determined by its context. In some languages translators may be forced to choose a term here that refers either to a young child or to a teenage youth; and the choice will have to be made in the light of how old Ishmael is judged to be at the time of this story. See comments on the translation of the term “child” in verse 14.

And because of your slave woman: the two expressions starting because of … may often be combined to say “Don’t be upset about the boy and your slave woman.” See Good News Translation “Don’t be worried about the boy and your slave Hagar.”

Whatever Sarah says to you, do as she tells you is literally “All that Sarah says to you, listen to her voice.” We may also translate “Do whatever Sarah says” or “Do whatever Sarah tells you” (Good News Translation).

For through Isaac shall your descendants be named is literally “because through Isaac shall seed be called to you.” The sense of this statement is that Abraham’s descendants will be identified through Isaac’s line or, as New English Bible says, “because you shall have descendants through Isaac.” Compare with Rom 9.7; Heb 11.18. One translation that makes this completely clear says “Because my promise to you, that you will have many descendants, that will come true through Isaac.”

Quoted with permission from Reyburn, William D. and Fry, Euan McG. A Handbook on Genesis. (UBS Helps for Translators). New York: UBS, 1997. For this and other handbooks for translators see here .