“Let there be a door to thy mouth, that it may be shut when need arises, and let it be
carefully barred, that none may rouse thy voice to anger, and thou pay back abuse with abuse. Thou hast heard it read to-day: ‘Be ye angry and sin not.’ Therefore although we are angry (this arising from the motions of our nature, not of our will), let us not utter with our mouth one evil word, lest we fall into sin; but let there be a yoke and a balance to thy words, that is, humility and moderation, that thy tongue may be subject to thy mind.”
(St Ambrose ‘On the Duties of the Clergy’)