Saint Ambrose of Milan

To avoid dissensions we should be ever on our guard, more especially with those who drive us to argue with them, with those who vex and irritate us, and who say things likely to excite us to anger. When we find ourselves in company with quarrelsome, eccentric individuals, people who openly and unblushingly say the most shocking things, difficult to put up with, we should take refuge in silence, and the wisest plan is not to reply to people whose behavior is so preposterous. Those who insult us and treat us contumeliously are anxious for a spiteful and sarcastic reply: the silence we then affect disheartens them, and they cannot avoid showing their vexation; they do all they can to provoke us and to elicit a reply, but the best way to baffle them is to say nothing, refuse to argue with them, and to leave them to chew the cud of their hasty anger. This method of bringing down their pride disarms them, and shows them plainly that we slight and despise them. 

-- Saint Ambrose of Milan