The Scriptures must be reliable, for they are the foundation of Christianity. Without the Scriptures, our Faith will fall. Thus, through the centuries, Christ's enemies have concentrated their attacks on the inerrancy, the sufficiency, and the clarity of the Bible, alleging that it contains errors, is inadequate, or is in need of an interpreter.
Such attacks come from papists, zealots, modernists, and unbelievers of various other sorts. God has used these attacks as goads to prod Christian thinkers into defending his Word. Louis Gaussen's God-Breathed is one of the greatest defenses of Scripture ever penned.