John Piper had a post recently on the Desiring God blog that provided an excellent insight. There Piper made a plea for regular: (1) personal mediation on Scripture and (2) regular study in a class or in a book from a wise and godly teacher. Here is an excerpt:
The reason I plead for both is that without a book or a class about what some part of the Bible means and a teacher who is ahead of you, your devotions will probably flatten out at a low level of insight.
Year after year you will go over the same biblical ground and find it as perplexing as before. There will be little advance in understanding. This will tend to take the heart out of devotional reading, because the lack of growth cannot sustain the joy.
Piper’s point helps me see why I would want to read books that aren’t inspired by God: because they can help me better understand the one that is.
Lately, I have been praying when I read books other than Scripture that through reading the book God would help me to better understand and apply Scripture to my life. If a book (those written about spiritual matters) does this, then it is helpful. If it doesn’t … I wonder how helpful it really is.