The Bible is the ultimate book. So teaches Hebrews chapter 4.
Take God out of the picture and nothing makes sense at all. Notice the connection here between God's "word" and our "word":
There is a deliberate interpay here between logos in verse 12 and logos in verse 13. God gives us his word of revelation. We give him our word of explanation after we die. "We must," the Living Bible says, "explain all that we have done."
That, my friends, is why we read the Scriptures more than any other book. That's why we take them very seriously. The Scriptures warn and educate us. We can learn from the old mistakes people made when we read the Scriptures. The Scriptures and the Scriptures alone can penetrate our innermost thoughts and desires, exposing us for who we really are. God's word is a living word. Other books are dead. Other books become specialist's reading only, like Plato. Who would dream of having their daily devotions from Plato's Lysis, Phaedo, Symposium, or Republic? But millions read the Bible daily. As a Chinese Christian once put it, "The one who made this book made me."
So we persevere in our resolve to read and study the word of God. The author of Hebrews -- I'm convinced it's Paul -- is emphatically not a pragmatist. He is first and foremost a theologian, but one who is concerned to allow his beliefs to determine his actions. None of us could ever give an acceptable account to God unless God himself had taken the initiative to reveal his will to us.
The word of God is the sword of the Spirit. As John Stott once said, "The Spirit without the word is weaponless. The word without the Spirit is powerless." God grant that our lives may be characterized by this great truth.