From the GARBC URL
Biblical Authority
The Bible is the final authority in all matters of belief and practice because the Bible is inspired by God and bears the absolute authority of God Himself. Whatever the Bible affirms, Baptists accept as true. No human opinion or decree of any church group can override the Bible. Even creeds and confessions of faith, which attempt to articulate the theology of Scripture, do not carry Scripture’s inherent authority.
2 Timothy 3:15-17; 1 Thessalonians 2:13; 2 Peter 1:20, 21
Please define "practice." Is it restricted to how we worship God?
How do you apply the regulative principle? see
http://en.wikipedia.org/wiki/Regulative_principle_of_worship
The regulative principle of worship is a teaching shared by some Calvinists and Anabaptists on how the Bible orders public worship. The substance of the doctrine regarding worship is that God institutes in the Scriptures everything he requires for worship in the Church and that everything else is prohibited. The term "regulative principle" is less frequently broadened to apply to other areas such as church government (Thornwell, 1841-2), but in this sense it becomes synonymous with the principle of sola scriptura.
The regulative principle is often contrasted with the normative principle of worship which teaches that whatever is not prohibited in Scripture is permitted in worship, as long as it is agreeable to the peace and unity of the Church. In short, there must be agreement with the general practice of the Church and no prohibition in Scripture for whatever is done in worship.
The normative principle of worship is the generally accepted approach to worship practiced by Anglicans, Evangelicals, and Methodists. The regulative principle of worship is generally practiced by the conservative Reformed churches, Restoration Movement, and in other conservative Protestant denominations, and it finds expression in confessional documents such as the Westminster Confession of Faith (see Chapter 21), the Heidelberg Catechism, the Belgic Confession, and the London Baptist Confession of Faith.