Here's a great article that Justin Taylor wrote for the June 09 edition of Tabletalk.
A Teachable Spirit
In it he says:
"Only one book is absolutely essential to save us, to equip us to obey God’s will, and to glorify Him in whatever we do. Only one book gives us undiluted truth — the whole truth and nothing but the truth. Only one book serves as our ultimate and final authority in all that it affirms. That book, of course, is the Bible, God’s Holy Word. No wonder John Wesley once exclaimed, “Let me be homo unius libri” — a man of one book!
And yet the irony is that if we use only this book, we may in fact be in disobedience to it."
HT:Crossway Blog