Quintilian Institutio Oratoria 5.11.13

[13] Arguments from unlikes present great variety, for they may turn on kind, manner, time, place, etcetera, almost every one of which Cicero employs to overthrow the previous decisions that seemed to apply to the case of Cluentius, ¹ while he makes use of argument from contraries when lie minimises ² the importance of the censorial stigma by praising Scipio Africanus, who in his capacity of censor allowed one whom he openly asserted to have committed deliberate perjury to retain his horse, because no one had appeared as evidence against him, though he promised to come forward himself to bear witness to his guilt, if any should be found to accuse him. I have paraphrased this passage because it is too long to quote.