Abraham’s defense grows weaker as he finds more excuses for his deceit.

Besides she is indeed my sister: Besides is a term that means “also,” “in addition,” “as well.” Here it marks the introduction of a second excuse. In the Law (see Lev 18.9, 11; 20.17; Deut 27.22) marriage between such brothers and sisters was prohibited at later periods in Israel, although it was practiced among the Canaanites (as Driver states) and may have been permitted at the time of King David (2 Sam 13.13).

Indeed translates a Hebrew form that emphasizes the word or statement that follows: “here indeed,” “in fact,” “in truth.” This emphasis is accomplished in Good News Translation by “really.” Revised English Bible has “She is in fact….” This claim will be modified in the following clause. For sister see comments on Gen 20.2.

The daughter of my father but not the daughter of my mother: these two phrases explain the clause before them, and in Revised Standard Version they are separated from it by a comma. In other languages it may be necessary to begin a new sentence: “She is the daughter of….” If the Hebrew manner of expressing the relationship is not satisfactory, we may also say, for example, “My father was her father but my mother was not her mother” or “She and I had the same father but not the same mother.”

And she became my wife: in some languages this statement may require a transition; for example, “When we grew up, she [Sarah] became my wife” or “Later, I married her.”

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 .