“According to the above mentioned principles, all doctrines must be conformed, and that which is contrary to them, must be rejected and condemned, as being repugnant to the unanimous declaration of our faith.
In this manner the difference between the holy Scriptures of the Old and New Testaments and all other writings, will be preserved, and the holy Scriptures alone will remain as the sole judge, rule, and standard, according to which, as the only touchstone, all doctrines shall and must be understood and judged whether they be good or evil, right or wrong.
But the other symbols and writings mentioned above, are not authorities like the holy Scriptures; but they are only a testimony and explanation of our faith, showing the manner in which at any time the holy Scriptures were understood and explained by those who then lived, in respect to articles that had been controverted in the church of God, and also the grounds on which doctrines that were opposed to the holy Scriptures, had been rejected and condemned” (Formula of Concord, Epitome, Rule and Standard, Henkel p. 554)