Genesis 12:11-13

and it cometh to pass as he hath drawn near to enter Egypt, that he saith unto Sarai his wife, `Lo, I pray thee, I have known that thou art a woman of beautiful appearance;

and it hath come to pass that the Egyptians see thee, and they have said, `This is his wife,' and they have slain me, and thee they keep alive:

say, I pray thee, thou art my sister, so that it is well with me because of thee, and my soul hath lived for thy sake.'