The Institutes, Book 8
The Added Words Without a Cause
But you should know that in this verse, which in many copies reads, “Whoever is angry with his brother without a cause is in danger of the judgment,” the words “without a cause” are superfluous. They were added by those who did not think that anger for just causes ought to be banished, since certainly nobody, however unreasonably he is disturbed, would say that he was angry without a cause. So the phrase appears to have been added by those who did not understand the drift of Scripture, which meant to banish the provocation to anger altogether and to leave no occasion whatever for indignation; for fear that, while we were commanded to be angry with a cause, an opportunity might come our way for being angry without one. For the end and aim of patience lies not in being angry for a good reason, but in not being angry at all. I know, of course, that some take this very phrase, “without a cause,” to mean that a man is angry without a cause when, being angered, he is not allowed to seek revenge. But it is better to take the verse as we find it written in many modern copies and in all the ancient ones.