The KJV says:
"And the man that committeth adultery with another man's wife, even he that committeth adultery with his neighbour's wife, the adulterer and the adulteress shall surely be put to death." (Leviticus 20:10)
The Hebrew says:
ואיש אשר ינאף את־אשת איש אשר ינאף את־אשת רעהו מות־יומת הנאף והנאפת׃
In the Hebrew there is an apparent repetition of the phrase "איש אשר ינאף את־אשת (a man who commits adultery with a woman)". The literal translation of the verse from Hebrew could read:
"And a man who commits adultery with the wife of a man who commits adultery with the wife of his neighbor shall surely be put to death, the adulterer and the adulteress."
On the face of it, the verse appears to say that it is an offence to commit adultery with the wife of a man who commits adultery with the wife of his neighbor. Such a sentence seems awkward. Thus some translations (e.g. ESV, NLT) have omitted the repeating clause. However, the awkwardness is due to there being no punctuation in the Hebrew. The sentence makes sense when it is punctuated correctly. Consider the same literal translation with punctuations provided in the following manner:
"And a man who commits adultery with the wife of a man (who commits adultery with the wife of his neighbor) shall surely be put to death, the adulterer and the adulteress."
When the words are grouped into clauses in this manner, the repetition makes sense. The first clause includes the words "And a man who commits adultery with the wife of a man". The second clause, which is a parenthetical clarification of the first clause, includes the words "who commits adultery with the wife of his neighbor". The second "who" points to the first occurrence of "man" (the adulterer) as the antecedent.
It has been alleged that Hebrew parallelism does not repeat the exact same words. But although the words at Leviticus 20:10 may be identical according to a certain grouping of words, the clauses are not identical if the words are grouped as suggested above. The parallelism at Leviticus 20:10 provides for the clearest statement of the law. In Hebrew, the same word "ishah" is used to mean "woman" and "wife". To ensure that the reader understands "ishah" at Leviticus 20:10 to mean "wife" (a married woman), the clearest way to do so is to say "man's ishah". A "neighbor's ishah" could technically mean "neighbor's woman" which could refer to a female neighbor's unmarried daughter. But Leviticus 20:10 is specifically prohibiting adultery with a married woman. The reference to a "man's ishah" closes off this legal loophole. The reference to a "neighbor's ishah" in the parallel clause further clarifies the law by drawing attention to the fact that adultery is a sin against one's neighbor. As "Thou shalt love thy neighbour as thyself" is the law fulfilled in one word (Galatians 5:14), it is most fitting that the prohibition against adultery makes a connection to the ultimate prohibition of offending one's neighbor.
The KJV supplies the words "even he" in italics instead of parentheses to provide the same effect of rendering the second clause as a clarification of the first. The NKJV, NASB and NIV (1984, TNIV, 2010) also treat the Masoretic text here as being without error.
Read more articles from: The King James Version is Demonstrably Inerrant
Also read: Masoretic Readings Defended