Carl Trueman’s has written here on the issue of “the problems caused by words that create hurt or are spiteful, words that reshape our realities in ways that do us harm on numerous levels” and what Luther has to say on it. Here are a couple of clips:
Luther emerged from a medieval philosophical tradition which accented the reality and the power of words and which had come to drive something of a wedge between things and words, stressing the latter as constructive of what was known.
In other words, others might tell me I am a failure, an idiot, a clown, evil, incompetent, vicious, dangerous, pathetic etc., and these words are not just descriptive: they have a certain power to make me these things, in the eyes of others and even in my own eyes, as self-doubt creeps in and the Devil whispers in my ear. But the greatness of Luther’s Protestantism lies in this: God’s speaks louder, and his word is more powerful. You may call me a liar, and you speak truth, for I have lied; but if God declares me righteous, then my lies and your insult are not the final word, nor the most powerful word. I have peace in my soul because God’s word is real reality.