If now some know-it-alls object and say, “Well, even if somebody is not baptized with outward water, he can still believe, change and improve his life, and live according to the Rule of Christ. Therefore, baptism is not necessary.” Answer: You highly learned people should have made this objection not to me but to Christ himself, and that before he instituted baptism, so that he could have refrained from it. But at that time you were not his counselors. I realize it was a great oversight.
On the Christian Baptism of Believers by Balthasar Hubmaier