13. 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.” Ps. iv. 4. 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. Let it be held in check with a tight rein; let it have its own means of restraint, whereby it can be recalled to moderation; let it utter words tried by the scales of justice, that there may be seriousness in our meaning, weight in our speech, and due measure in our words.