Living, nay dying and being damned, make a theologian, rather than comprehending, reading, or speculating.
The original reads:
Vivendo, immo moriendo et damnando fit theologus, non intelligendo, legendo aut speculando.
The source in a 1520 lecture on Psalm 5:11 ("let all those that put their trust in thee rejoice," etc.), reprinted in the Weimarer Ausgabe, vol. 5, p. 163, lines 29-30. The source is often cited on web pages, although we suspect strongly that many of these sites are copying from each other.
We took a moment to confirm the citation, using the astonishing Internet Archive. More than a moment, actually, since the enormous file slowed our browser to a crawl. Thanks, Uncle Marty, for your legendary logorrhea.
Writers generally use the remark as a prooftext for what may be called the existential side of Luther's theology, the sense of personal struggle against sin, death and Hell. They are surely right to do so, at least within limits. (We stumbled over an LCMS document that seems to use it as a model for seminary education. No comment.)
What we have not seen mentioned is the context. The much-quoted remark follows a passage that says, very roughly, this:
I would want to be warned that it is said, from Italy all the way to Germany, in the Commentary on the Mystical Theologians of Dionysius: that it is merely an annoying display of one's own learning, not to truly be a mystical theologian, but to read, teach and understand this, or to understand and teach what the vision was.
Okay, that's a junk translation, and we apologize. But do you see the point? Both remarks make a distinction between a true theologian and merely learned person -- a useful distinction. But it is by no means original to Luther, who is here restating for his students a remark he has himself found in the writer now generally identified as Ps-Dionysius (or maybe a commentary on Ps-Dionysius).
This matters, at least a little, because so many Protestant theologians have an abiding hatred for the rehashed neoplatonism of Ps-Dionysius, with its ladders of being which extend from heaven straight through the earth, and which were used to reinforce the rigid social and ecclesiastical hierarchy of the Middle Ages. (Indeed, Ps-D. seems to have invented the word hierarchy). We had two different professors at two different seminaries who assigned this guy, merely in order to refute him.
We do not doubt that Luther himself eventually had some harsh words for Pseudo-Dionysius. He had harsh words for everybody, to be frank. But it may be useful to remember that one of Luther's most frequently repeated remarks, and one of lasting value, was intended as a no more than a reflection of something the other guy said first. We expect there's a moral in there, about listening to people we disagree with, and not throwing out the good ideas with the bad ones.
Happy Reformation Day, everybody!