Found an interesting comment today that encapsulates the heart of the Anabaptist position regarding orthodoxy. The Dutch Mennonite elder Tieleman Jansz van Braght (1625-1664) in his work the Martyrs Mirror: The Story of Seventeen Centuries of Christian Martyrdom From the Time of Christ to A.D. 1660 during the course of his analysis of the Council of Nicea he presented the epitome of the Anabaptist’s position on the historic orthodox creed.
This is the great Council which is extolled as orthodox and Christian by nearly all so-called Christians. Be this as it may, we see no reason to praise it so highly, seeing that we must honor the precepts of God’s holy Word alone, whereas the rules of that council were made by fallible men. Yet, so far as these men have laid down precepts that accord with the precepts of God’s holy Word, or, at least, do not militate against them, so far we accept, or, at least, do not oppose them.
Scripture was the Anabaptist’s standard for determining those in the Body of Christ. Scripture was the means for defining the nature of God. The Christological narrative that they found in scripture was the foundations for their principal teachings and praxis. The above principal would apply across the board to include Niceno–Constantinopolitan, Chalcedon and Athanasian or any other historic ecumenical statement of belief that originated leading to or during the “Constantinian shift” or “reversal”.