Aulus Gellius, Attic Nights 12.12
12 The clever response of Marcus Cicero as he defends himself against a claim of obvious lying
“This is a part of rhetorical training too—to admit criminal matters not subject to danger cleverly and with charm so that, if something foul is alleged which cannot be denied, you may defuse it with a humorous response and make the whole matter more dignified with a joke rather than an allegation, just as it is recorded that Cicero did when he tempered what could not be denied with a clever and amusing comment.
For when Cicero wanted to purchase a house on the Palatine hill and he did not have the money at hand, he accepted in private as much as two million sesterces [$100,000?] from Publius Sulla* who was then a defendant in a case. But the whole matter was made public before he bought the house and he was charged with receiving money for buying a house from an accused defendant. So then, troubled by the unanticipated criticism, Cicero denied that he had received the money and denied that he would have bought the house, saying “Indeed, If I buy the house, it is true that I took the money”.
But later, when he had bought the house and was charged with being a liar in the senate by his enemies, he laughed plenty and said while chuckling: “You are senseless men if you don’t know that it is a mark of a wise and cautious head of a family, when he wants to buy something, to deny that he wants to buy it to scare off competitors!”
*He was charged for participating in the conspiracy with Cataline.
XII Faceta responsio M. Ciceronis amolientis a se crimen manifesti mendacii.
 Haec quoque disciplina rhetorica est callide et cum astu res criminosas citra periculum confiteri, ut, si obiectum sit turpe aliquid, quod negari non queat, responsione ioculari eludas et rem facias risu magis dignam quam crimine, sicut fecisse Ciceronem scriptum est, cum id, quod infitiari non poterat, urbano facetoque dicto diluit.  Nam cum emere uellet in Palatio domum et pecuniam in praesens non haberet, a P. Sulla, qui tum reus erat, mutua sestertium uiciens tacita accepit.  Ea res tamen, priusquam emeret, prodita est et in uulgus exiuit, obiectumque ei est, quod pecuniam domus emendae causa a reo accepisset.  Tum Cicero inopinata obprobratione permotus accepisse se negauit ac domum quoque se empturum negauit atque ‘adeo’ inquit ‘uerum sit accepisse me pecuniam, si domum emero’. Sed cum postea emisset et hoc mendacium in senatu ei ab inimicis obiceretur, risit satis atque inter ridendum: ‘ἀκοινονόητοι’ inquit ‘homines estis, cum ignoratis prudentis et cauti patrisfamilias esse, quod emere uelit, empturum sese negare propter competitores emptionis.’