Incest
History
The earliest Biblical reference to incest involved Cain. It was cited that he knew his wife and she conceived and bore Enoch. During this period, there was no other woman except Eve or there was an unnamed sister and so this meant Cain had incestuous relationship with his mother or his sister. According to the Book of Jubilees, Cain married his sister Awan. Later, in Genesis 20:12 of the Hebrew Bible, the Patriarch Abraham married his half-sister Sarah. Other references include the passage in Samuel where Amnon, King David's son, raped his half-sister, Tamar. According to Michael D. Coogan, it would have been perfectly all right for Amnon to have married her, the Bible being inconsistent about prohibiting incest.
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