"Whoever has gone astray in the faith may thereafter believe whatever he wants to, everything is equally valid."

"Wer des glaubens gefeilet hat, der mag darnach glewben was er wil, gilt eben gleich."

     Martin Luther, Sermon Von dem Sacrament des leibs vnd bluts Christi, widder die Schwarmgeister (1526), in WA 19 (1897), 484 ll. 19–20, as trans. Brad Gregory in chap. 2 of The unintended Reformation:  how a religious revolution secularized society (Cambridge, MA:  The Belknap Press of Harvard University, 2012).  =LW 36 (The sacrament of the body and blood of Christ—against the fanatics), 336, as trans. Frederick C. Ahrens:

"Anyone who has failed to grasp the faith may thenceforth believe whatever he likes, it makes no difference."