Sola Scriptura: The Scripture Alone is the Standard
The doctrine that the Bible alone is the ultimate authority was the "Formal Principle" of the Reformation. In 1521 at the historic interrogation of Luther at the Diet of Worms, he declared his conscience to be captive to the Word of God saying, "Unless I am overcome with testimonies from Scripture or with evident reasons -- for I believe neither the Pope nor the Councils, since they have often erred and contradicted one another -- I am overcome by the Scripture texts which I have adduced, and my conscience is bound by God's Word." Similarly, the Belgic Confession stated, "We believe that [the] holy Scriptures fully contain the will of God, and that whatsoever man ought to believe unto salvation is sufficiently taught therein...Neither may we consider any writings of men, however holy these men may have been, of equal value with those divine Scriptures nor ought we to consider custom or the great multitude, or antiquity, or succession of times and persons, or councils, decrees or statutes, as of equal value with the truth of God... Therefore, we reject with all our hearts whatsoever does not agree with this infallible rule" (VII). As the Scripture says,
Open my eyes, that I may behold Wonderful things from Thy law....I will bow down toward Thy holy temple, And give thanks to Thy name for Thy lovingkindness and Thy truth; For Thou hast magnified Thy word according to all Thy name....You, however, continue in the things you have learned and become convinced of, knowing from whom you have learned them; and that from childhood you have known the sacred writings which are able to give you the wisdom that leads to salvation through faith which is in Christ Jesus. All Scripture is inspired by God and profitable for teaching, for reproof, for correction, for training in righteousness; that the man of God may be adequate, equipped for every good work. (Psalm 119:18; Psalm 138:2; II Tim. 3:14-17)