A good question! (Genesis 20:12 vs Leviticus 18:11, 20:17)
If we assume that the Bible is a perfectly orchestrated book, in the words of some believers, “infallible”, something that is error free, written by the pen of an author who is basically quoting God from heaven, without his own views as he writes, then the Bible is full of some serious problems. All you have to do to prove that these problems exist is to read the Bible. It doesn’t take a knowledge of Hebrew or very much time. Just read it for yourself, and you will see what I mean. You will read it and have many questions.
One of these questions that the Bible addresses that should be simple to answer is whether or not it is okay to marry your sister. If we read the text of Genesis, and the story of Abraham, we come to the conclusion that Abraham married his sister. From Genesis 20:12 we read these words from the mouth of Abraham:
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.
These verses in Genesis 20 come to us from the Elohist source, 1 and are thus most likely much older than that of the scriptures that we read in Leviticus (written by the Priestly author) that prohibit a man from marrying his sister. By the time that the Priestly writer put down the prohibition concerning marrying one’s sister, much time had elapsed. Views had changed regarding this law. And this is why we have so many problematic issues like this in the Bible. The Bible is a collection of books that were written over many centuries. As these books were assembled, redacted, rewritten and “textualized”, contradictions like this one came to be the norm. 2
The laws that the Priestly writer himself wrote or preserved, since they may well have been part of the tradition that he himself inherited, are all prefaced by the phrase “And the Lord (Yahweh) spoke to Moses saying. . .” (see for example Leviticus 18:1 KJV) When we read the Priestly author’s prohibition against marrying your sister we read the following:
The nakedness of thy father’s wife’s daughter, begotten of thy father, she is thy sister, thou shalt not uncover her nakedness. (Leviticus 18:11 KJV)
Nakedness in the context of this verse means to have sexual relations. 3 This verse is a prohibition of intimacy with one’s sister. Later we read:
And if a man shall take his sister, his father’s daughter, or his mother’s daughter, and see her nakedness, and she see his nakedness; it is a wicked thing; and they shall be cut off in the sight of their people: he hath uncovered his sister’s nakedness; he shall bear his iniquity. (Leviticus 20:17 KJV)
It is likely that these verses by the Priestly author were written after Israel had been exposed to the morals of those that they had lived among – the Egyptians, the Canaanites, and perhaps even those in Babylon. The prohibition of relations with your sister would have set the Israelites apart from the practices of these peoples, people that from the perspective of the author of Leviticus, were unholy and impure. By not participating in these practices, Israel was maintaining a distance from the world, and therefore striving to be found worthy of the calling that the Lord had put upon them (see Exodus 19:6). It is unlikely that the author who penned the story of Abraham marrying his sister had such views. It was an earlier time, and these views had not yet crystallized in the minds of the authors of the Priestly text. At any rate, this is a tenable explanation for the contradiction, for a contradiction it is, and it is a whopper.
- Richard Friedman, The Bible with Sources Revealed, Harper One, 2003, p. 62
- Ann Loades, Michael McLain, Hermeneutics, the Bible and Literary Criticism, Palgrave Macmillan, 1992, p. 6. David Klemm writes, “The word ‘text’ comes from the Latin textus, meaning that which is woven, as past participle of texere, ‘to weave’.”
- Michael Coogan, God and Sex: What the Bible Really Says, p. 10-11.