Verse 36 introduces Isaac as Abraham’s heir, the one who will possess Abraham’s wealth when he dies.
Sarah … bore a son: that is, “gave birth to a son” or “gave him [Abraham] a son.” Sarah has died before the events of this chapter take place, and in some languages translators will have to take this into account in referring to her; for example, “Sarah, that dead wife of my master, left behind a son. She had that son when she was an old woman.”
When she was old: in 21.2 a similar statement is made, in which Sarah gives birth “in his [Abraham’s] old age.” Here in verse 36 the Septuagint has “in his old age.” However, Hebrew Old Testament Text Project rates the Hebrew text as {A}, “in her old age,” and recommends the wording of Revised Standard Version and Good News Translation.
And to him he has given all that he has: the masculine singular pronouns may need to be clarified by saying, for example, “And Abraham [my master] has given his son all that my master has.” The underlying message is that Laban and Bethuel would be wise to form an alliance through marriage with the heir of Abraham’s great wealth.
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 .