Check out this very good article on the meaning of Biblical authority, written by Gerhard Forde. It's not what you usually think:
Gnesio » Articles » The Authority of Scripture
The authority of Scripture is, simply put, Gospel. It is neither bondage to our selfish desires nor being bound to laws and regulations. It is a charter of freedom! The Word of God makes us free through the promise of forgiveness. It kills our old self with its selfish desires, to have what one wants and succeed in doing good, and makes us alive in Jesus Christ. Bye bye, sin and law! We have a new master - a Lord who is uncompromisingly loving and creates new out of nothing! This is our life, meant for all: faith in the grace and power of infinite Love who is a Person. He is Jesus Christ, the Son of God, who died for you and me - to make us alive and renewed in joy.