I Need to Be Careful About Buying Books from a Christian Bookstore

After I got saved, I wanted to get good Christian books. I just wanted to buy everything and I remembered saving up money to buy some books that were written by quack preachers. Years later, I started to be more selective the more I matured in the faith. Here's an excerpt from John F. MacArthur's book "Fool's Gold" from page 45 by co-author Nathan Busenitz:
"Outside the local church there is no probably no place in the community with more spiritual influence than the local Christian bookstore. For many believers, books provide the primary supplement to what is heard on Sundays. But just because something on the shelf doesn't mean it is doctrinally accurate or spiritual beneficial. After all, biblical discernment is not just for sermons. It must also be applied to chapters and articles. Even best sellers are not above the scrutiny of Scripture." 

Yes there are a lot of best sellers. Purpose Driven Life is a best seller but the whole book preaches a watered down presentation of the Gospel of Jesus Christ. Worse, Rick Warren has openly shown that he's a pro-Vatican preacher. A lot of other books I wanted to collect were written by Billy Graham, Joyce Meyer, Joel Osteen and Robert Schuller. Others are just a series of unproven conspiracy theories filled with questionable content. Many may be filled with truth but aren't the right way to do witnessing and apologetics with followers of false religion. 

As Charles H. Spurgeon said, "Read many good books but live the Bible." The principle is Sola Scriptura. It means Scripture is the sole principle that one must filter right and wrong with spiritual matters. While wide-reading is a must and good research helps me defend the faith but I must also watch out for faulty sources.