Cato the Younger (17.3-17.4)

In the next place, though many used improper methods to get writings filed with the quaestors, and though previous quaestors had been accustomed to receive false decrees at the request of those whom they wished to please, nothing of this sort could be done now without Cato finding it out. Indeed, on one occasion when he was doubtful whether a certain decree had actually passed the senate, though many testified to the fact, he would not believe them, nor would he file the decree away until the consuls had come and taken oath to its validity.

Again, there were many persons whom the famous Sulla had rewarded for killing men under proscription, at the rate of twelve thousand drachmas. All men hated them as accursed and polluted wretches, but no one had the courage to punish them. Cato, however, called each one of these to account for having public money in his possession by unjust means, and made him give it up, at the same time rebuking him with passionate eloquence for his illegal and unholy act.