And Sarah conceived: it may be necessary to use a connecting expression that shows the link between verses 1 and 2; for example, “And so,” “Therefore.” Conceived means she became pregnant.

Bore Abraham a son: that is, “gave Abraham a son,” “had a son with Abraham.”

In his old age: that is, “when he was old.”

At the time of which God had spoken to him: this refers back to God’s promise of a son to the aged Abraham in chapter 18. The time refers to the time mentioned in 18.10, 14. Note how Good News Translation has rephrased the second clause as an independent sentence: “The boy was born at the time God had said he would be born.” Other translations that follow this approach say, for example, “Sarah gave birth at the [exact] time God had indicated earlier.”

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 .