Institutio Oratoria

But there are so he who, even although the cases which they have undertaken give but small scope for eloquence, none the less trick it out with matter drawn from without and, if all else fails, fill up the gaps in their case with abuse of their opponents, true if possible, but false if necessary, the sole consideration that weighs with them being that it affords exercise for their talents and is likely to win applause during its delivery. Such conduct seems to me so unworthy of our perfect orator that, in my opinion, he will not even bring true charges against his opponents unless the case demand.