Why Abimelech Feared to Take Rebekah, Isaac's Wife

"One of the people might easily have lain with your wife" (Genesis 26:10). Now Abimelech did not wish to take her, even though he said, "She is my sister," for he was afraid that there might befall him what had befallen him concerning Abraham his father, who said of Sarah, "She is my sister"; and when he took her, the Holy One, blessed be He, shut up his whole household, and He said to him, "Behold, you are a dead man because of the woman whom you have taken" (Genesis 20:3). Therefore Abimelech would every day observe Isaac, to see whether Rebekah was his sister or his wife. And Isaac would guard himself not to lie with her, because he had said, "She is my sister." But when the days grew long for him there, for he spent the whole summer, he said: Surely Abimelech has forgotten, and he lay with her. And Abimelech, who was watching whether she was his sister or his wife, when he saw him sporting with her, for the sporting was an act of marital intimacy, immediately Abimelech called him and said to him, "One of the people might easily have lain with your wife." And who is the singular one? This is the king.