M. Tullius Cicero Pro A. Cluentio 140

[140] They say that that able man, Marcus Antonius, was accustomed to say, “that he had never written a speech, in order that, if at any time he had said anything which was not desirable, he might be able to deny that he had said it.” Just as if whatever were said or pleaded by us was not retained in men's memories, if we did not ourselves commit it to writing. 51
  But I, with respect to speeches of that sort, am guided by the authority of many men, and especially of that most eloquent and most wise man, Lucius Crassus; who—when he was defending Lucius Plancius, whom Marcus Brutus, a man both vehement and able as a speaker, was prosecuting; when Brutus, having set two men to read, made them read alternate chapters out of two speeches of his, entirely contrary to one another, because when he was arguing against that motion which was introduced against the colony of Narbo , he disparaged the authority of the senate as much as he could, but when he was urging the adoption of the Servilian law, he extolled the senate with the most excessive praises; and when he had read out of that oration many things which had been spoken with some harshness against the Roman knights, in order to inflame the minds of those judges against Crassus—is said to have been a good deal agitated.