Genesis 20:2

And Abraham said of Sarah his wife, she [is] my sister,.... This he gave out in all conversation he came into, and said it to every one that asked who she was, which was little better than a lie; it at least was an equivocation and deception, and not at all justifiable, and tended to expose his wife's chastity, and discovered a distrust of divine Providence; the same infirmity be had given way to, and the same evil he had fallen into in Egypt, Genesis 12:11, and therefore was the more inexcusable now; good men not only fall into sin, but have their relapses:

and Abimelech king of Gerar sent and took Sarah; having heard or seen what a beautiful woman. Sarah was, though ninety years of age, having never bore children; and understanding she was a single person, sent his servants to take her, and bring her to his house, in order to be his wife, which seems to be done with some kind of force; and it can hardly be thought that Abraham and Sarah would freely agree to it, at least it must be done with reluctance on their parts. Whether Abimelech was the first king of Palestine of this name, is not certain; if he was, which is not improbable, it became usual afterwards for the kings thereof to be so called, as Pharaoh was a common name to the kings of Egypt; it signifies "father" and "king", as kings should be the fathers of their people.