God alone is our teacher and we do not go beyond what he has commanded.

"Teaching and doing are two things. I say, furthermore, that one should separate teaching and doing as far from each other as heaven from earth. Teaching belongs only to God. He has the right and the power to command, forbid, and be master over the conscience. However, to do and refrain from doing belong to us so that we may keep God's commandment and teaching. Where doing or to refrain from doing is in question, and concerning which God has taught, commanded, and forbidden nothing, there we should permit free choice as God himself has done. Whoever though goes beyond this by way of commandments or prohibition invades God's own sphere of action, burdens the conscience, creates sin and misery, and destroys all that God has left free and certain. In addition he expels the Holy Spirit with all his kingdom, work, and word, so that nothing but devils remain." - Martin Luther, Against the heavenly Prophets, Pg. 207

"Now, dear sirs, we are speaking of minor matters, insofar as the doing is concerned. For what does it mean to elevate the sacrament? But when the teaching is taken into account we are dealing with the most important matters. The factious spirit is too frivolous and meddles all too impudently in this matter. He has such a low regard for teaching and such a high regard for the doing that he does not see the beam in his own eye, and is too much concerned with the splinter in our eye [Matt. 7:5]. For with teaching he manhandles conscience, which Christ has won with his own blood, and kills souls, which God has dearly purchased, with commandments and sins. For thereby the kingdom of Christ will be destroyed and everything that the gospel has brought us exterminated. For Christ cannot remain in the conscience that goes whoring after alien teaching and the commandments of men. There faith must perish. Therefore let everyone know that Dr. Karlstadt has a spirit which is hostile to faith and to the whole kingdom of God, which be in turn would destroy with his conceit and human nonsense, as you may well understand from this part of the discussion and concerning which you will hear more later." - Ibid, Pg. 209