First and foremost, A.J. Jacobs is a great writer. Smart, self-deprecating, witty, and observant, he could write about anything and i'd be hooked. (Which explains why his first writing project, "The Know-It-All" did so well, despite being about him reading the encyclopedia.)
As far as great spiritual/religious wisdom goes, however, it's difficult to pick out any great, shining gems. First of all, his journey was so gradual and personal that you really have to read the whole thing to get anything major from it. I could quote some bits at you, but they wouldn't really give you a sense of what he's like, or how the Bible transformed his behaviors and mindset. I can tell you that there was a transformation, though.
Secondly, this is not a book written by someone spiritual/religious who was looking for deeper meaning or a higher purpose or anything like that. A.J. was not trying to expand his Biblical knowledge or firm up his theology or anything like that. He walked into this experiment as an agnostic-ish Jewish-ish New Yorker, and he was basically trying to see if walking the walk and talking the talk would do anything. It does some stuff, but if your heart's not in it there's a limit to what you'll experience. To his credit, he realizes this and acknowledges it.
Anyway, there are two things i'd like to take note of before moving on to the next book. The first one comes from one of A.J.'s many interviews with religious leaders and laypersons. "'Let me drop an atom bomb on you,' said this Karaite . . . 'You can't follow all of the Bible literally because we can't know what some of the words mean.'" We can make really good guesses about a lot of them, but for many words, guesses are all we really have. If God cared about us following the Bible literally, don't you think He would have provided a decoder ring?
The closing thought comes right after A.J.'s wife, Julie, gave birth to their twins. Reflecting on a Bible story that reminds him of his sons and of his crazy roller-coaster year, A.J. says this: "The Bible may not have been dictated by God, it may have had a messy and complicated birth, one filled with political agendas and outdated ideas -- but that doesn't mean the Bible can't be beautiful and sacred."
Next up: "A Year of Biblical Womanhood", by Rachel Held Evans. Stay tuned!