What does the Bible say about scripture's authority?

According to 2 Timothy 3:16-17, all scripture is given by inspiration of God and is profitable for doctrine, reproof, correction, and instruction in righteousness. This means that scripture serves as a complete guide for faith and practice, enabling the man of God to be perfect and thoroughly furnished for every good work. The authority of scripture stems from its divine inspiration and its role as the ultimate source of truth for believers, confirming the doctrines concerning God, man, and redemption.