And there was a famine in the land: and Abram went down into Egypt to sojourn there; for the famine was grievous in the land.
And it came to pass, when he was come near to enter into Egypt, that he said unto Sarai his wife, Behold now, I know that thou art a fair woman to look upon:
Therefore it shall come to pass, when the Egyptians shall see thee, that they shall say, This is his wife: and they will kill me, but they will save thee alive.
Say, I pray thee, thou art my sister: that it may be well with me for thy sake; and my soul shall live because of thee. Genesis 12:10-13
Abraham said of Sarah his wife, She is my sister: and Abimelech king of Gerar sent, and took Sarah.
But God came to Abimelech in a dream by night, and said to him, Behold, thou art but a dead man, for the woman which thou hast taken; for she is a man's wife.
But Abimelech had not come near her: and he said, LORD, wilt thou slay also a righteous nation?
Said he not unto me, She is my sister? and she, even she herself said, He is my brother. Genesis 20:2-5