Speak not harshly

Speech is of two kinds – harsh and mild. In angry and cruel mood, it is crude; and mild when one is humble and quiet. Speech of kindness, compassion, sympathy, love, relations, affection, and deceit is mild. Against this, speech of cruelty, aversion, anger, haughtiness is discordant.

Everyone likes the voice of a cuckoo and peacock but nobody likes the voice of a crow and a donkey. This is the reason.

Men must learn a lesson from the beauty of nature. Man speaking harshly generates enmity; but friends will always surround the person speaking mildly and humbly. Voice of humility attracts, coarse voice repulses. Voice of a preacher must always be attractive so that he can very well influence and inspire his listeners. He must never use harsh language.

- Acaranga Sutra 2/1/6