If a doctrine is not found in Scripture, then it is to be rejected. Historical witness is indeed important, but is quite worthless as a definitive source of certainty outside of the criterion of the Scripture. All things are to be tested by the Scripture and no doctrines are to be received outside of the Scripture. The only certain apostolic witness is in the Scripture. Also, most of the pre-eminent traditions in any church of any age are diametrically opposed to the Bible. Scripture is not merely materially sufficient, it is entirely sufficient for every matter of faith and life, for everything pertaining to life and godliness. There is no other revelation in this dispensation and no other inspired source necessary or capable of either adding to or clarifying the Scriptures (i.e., the Scriptures are the only rule and criterion for faith and practice and nothing can be held to be equal with them at all). We must hear God's voice alone as speaking with authority. Sola Scriptura!