You specifically typed Martin Luter, not Martin Luther. And I was able to find references to people named Martin Luter.
It doesn't change the fact that it's an appeal to authority. Not surprisingly, there are people out there that aren't all that big on religion, so they'll twist words around to make a point. Martin Luther would fit that bill quite appropriately, especially seeing as he was excommunicated for his work.
You see this type of appeal to authority used ALL THE TIME. People will use an anecdote to make a point, and then say that Einstein said it because Einstein is a smart person and very introspective.
I use the definition of the word from a dictionary because, it's the definition of the word. Posting a dictionary/wiki definition is just as useful (if not more useful) than posting what some person said about it years ago.
My not understanding that you meant Martin Luther may not inspire confidence, but the fact that you used his quote as some sort of justification of your warped perception of the term faith doesn't do so either.