The more I study the Bible, the more I realize there is a considerable amount of value in better understanding the original languages, particularly idioms. The New Testament is interesting because whether it was written in Greek or Aramaic or both (I tend to lean toward believing the original language was mostly Aramaic with some Greek), there was no doubt about the Aramaic influences on the idioms used in scripture. Though I try to steer clear of any book that claims to hold a "key" to understanding the Bible, I would recommend George Lamsa's "
Idioms in the Bible Explained and a Key to the Original Gospel." I think Lamsa's understand of Aramaic is invaluable in understanding some of the idioms we wouldn't get otherwise. This pdf: "
Semitic Idioms in the New Testament, Suggest Peshitta Primacy – Part 1" is a good introduction to some Aramaic Idioms, though realize the authors are using this to support an Aramaic primacy. Like I said earlier, I tend to lean this way, but even if someone doesn't, the influence of the idioms of a highly spoken language of the time is important to understand. Paul Younan, a part author of the pdf, if one of the better modern references to Aramaic, and his opinions are highly trusted by many.
Another book I really enjoyed some time back is "
Misreading Scripture with Western Eyes: Removing Cultural Blingers to Better Understanding the Bible by E. Randolph Richards and Brandon J. O'Brien. Though I cannot recall if the book referenced polygyny at all, it is one of the books that reinforced the importance of understanding that framing the Bible in my cultural biases is not the way to read scripture. My life should be molded to God's ideal not God's ideal molded to my life. It helped me to step out of the highly Americanized gospel to see that those reading the original scriptures would have read some of it very differently than we do with our cultural biases.