No replies i see, but this uncritical RC quoting of quotes by Luther abounds, and even when they have a actual source, they are usually taken out of context. Thus i provided that of some quotes which a certain poster are pasted thrice today.
And therein i provide the best source for researching such quotes, and in which can be seen one of at least two posts by Swan addressing this statement, and sourced to Luther’s Sermons on John 16 [LW 24 (Luther's Works in English)]
Hope this helps.
Wherever the context is found, I would hope it is appended to further iterations of that quote. As it stands, the context missing, implies a falsehood. By referencing the document, the curious can read for themselves, and make their judgement as to whether the context or the implication of the quote is true.