Genesis 12:18

And Pharoh called Abram, and said, What is this that thou hast done to me? Why didst thou not show me that she is thy wife?

AND PHARAOH CALLED ABRAM. It is possible that when the plagues suddenly came upon him and his house at the very time Sarah was taken to his house, he thought to himself, What is this that G-d hath done unto us? And so he asked her, and she told him that she is Abraham’s wife. For this reason he called Abraham and accused him. Or it may be, as our Rabbis say, that Pharaoh was smitten with a certain skin disease which is aggravated by intimacy with a woman. Therefore he suspected that perhaps she is Abraham’s wife, and so he said to him with uncertainty, What is this that thou hast done unto me?, in order to draw the truth from him. Were she his sister, he would say, “Indeed, she is my sister.” And Pharaoh further said to him, Now therefore behold thy wife, take her, and go thy way. He said this in order to see what he would say, and now he would answer his reproof. But Abraham remained silent and did not answer him a word out of his great fear. Then Pharaoh understood that she is his wife as he had suspected, and then Pharaoh commanded his men to send him away.

למה לא הגדת לי, even if you had reason to suspect the ordinary citizens would harm you on account of her, surely you could have told me, the king, the truth, seeing that it is my task to rule with justice.