In response to the “brothers” of the Lord, the common Catholic response is that there was no word for cousin in Hebrew or Aramaic, and that they were translated into the Greek for brother for that reason. That seems a bit ad hoc, though; couldn’t God inspire a Greek text which would reflect what was actually meant by “brethren of the Lord”? Is there any extrabiblical evidence of something similar to this, where adelphos is used in Greek for cousins?
When one compares the Christian Greek Scriptures with the LXX, one sees that it was an accepted practice to use the koine Greek word “adelphos” for “cousin” even though Greek had its own word for this (anepsios).–See the LXX at Deuteronomy 23:7 and Jeremiah 24:9.
In fact, in the LXX the word “adelphos” is even used for “nephew” wherein Lot is called Abraham’s brother at both Genesis 13:8 and 14:14-16, even though Lot is the son of the brother of the patriarch.
The same occurs at Genesis 29:15 where Jacob and his uncle Laban are called “brothers.”
Why this was the practice may be answered in the way the Bible gets translated even today. The most popular or prefered way to translate Scripture among scholars and the public is “formal equivalence,” or “word-for-word.” Being that the Hebrew world of the time had no word for cousin, the “word-for-word” approach seems to have been adopted in both the translation of the Tanakh into Greek and the translation of Hebrew/Aramaic sources by the New Testament writers.
There are even instances among other words and expressions in the New Testament where it is clear that the writer was stumbling for a way to express something in the Greek that originated in the Semitic world of the Jews. At Luke 1:28 the expression in the Greek for “full of grace” is not the way it is written elsewhere, In fact it is unique. Luke used a word we find nowhere else in Greek literature and it is likely he was trying to capture from Mary’s testimony what she recalled the angel Gabriel saying to her. Since it is likely that Mary heard her language and not the koine Greek of Luke’s gospel, Luke used the inflectional character of koine Greek to fashion a word that still stumps translators to this day.
John 1 can seem contradictory if one does not know about or believe in the Trinity. The reason? Though written in Greek, the author was writing about Jewish concepts of Divinity. The Hebrew language did not have or use concepts later adopted to define the doctrine of the Most Holy Trinity at the time of John’s composition. Though we might be used to reading “the Word was with God” and “the Word was God,” these expressions are hard to fully grasp at first blush. They seem to go against logic because there was not a theological logic to define this concept yet. Therefore the author says things like 'God was God and was with God" from the beginning.
As to why God didn’t inspire the writers to do differently is something you will have to ask God. If you are look for etymological evidence that is so clear that all arguments about this stop, you won’t find that. Translators and authors didn’t leave us explanations as to word choices. We can only trace their steps the best way we can and make educated guesses.
