Institutio Oratoria

For it is a dog's eloquence, as Appius says, to undertake the task of abusing one's opponent, [*](A cognitor is one who represents another. The litigant may abuse his opponent, but that does not justify his advocate in doing so. ) and they who do so should steel themselves in advance to the prospect of being targets for like abuse themselves, since those who adopt this style of pleading are frequently attacked themselves, and there can at any rate be no doubt that the litigant pays dearly for the violence

of his advocate. But such faults are less serious than that which lies deep in the soul itself, making the evil speaker to differ from the evil doer only in respect of opportunity.