I’ve become convinced that one of Satan’s cleverest and most successful tricks is to get us reading all sorts of books to equip ourselves to serve God when scripture is itself sufficient for all things.
“All Scripture is God-breathed and is useful for teaching, rebuking, correcting and training in righteousness, so that the servant of God may be thoroughly equipped for every good work.” 2 Tim 3:16-17 (NIV)
I base my conclusion on seeing a veritable plethora of ads on Facebook waning me to buy this or that book to learn how to be successful in this or that Christian endeavor.
I think that Satan is at work because he knows that the Spirit of God who lives in us is most effective in our sanctification, maturity, and usefulness to God’s service when our learning comes through Holy Writ.
I’m not saying that reading other good Christian books is fruitless, but I am pointing to the primary and best source of Godly knowledge and spiritual power for the tasks of the Christian life.