Abraham said this lest they should slay him for his beautiful wife's sake, as himself tells us, Genesis 20:11. For though Sarah was ninety years old, yet she retained her beauty in good measure, partly, because she had not been broken by bearing and nursing of children; partly, because in that age of the world men and women, as they lived longer, so they did not so soon begin to decay, as now they do; and partly, because of God's especial blessing upon her. Abimelech took Sarah, not without violence, for it is not to be thought that either Abraham or Sarah would consent to it.
Related Commentaries of Genesis 20:2
Genesis 20:2
2 And Abraham said of Sarah his wife, She is my sister: and Abimelech king of Gerar sent, and took Sarah.