Cross reference
Genesis 20:12
12 And yet indeed she is my sister; she is the daughter of my father, but not the daughter of my mother; and she became my wife.
Genesis 11:29
29 And Abram and Nahor took them wives: the name of Abram's wife was Sarai; and the name of Nahor's wife, Milcah, the daughter of Haran, the father of Milcah, and the father of Iscah.
Genesis 12:13
13 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.
1 Thessalonians 5:22
22 Abstain from all appearance of evil.