Cato's assiduity also, and indefatigable diligence, won very much upon the people. He always came first of any of his colleagues to the treasury, and away the last. He never missed any assembly of the people, or sitting of the senate; being always anxious and on the watch for those who lightly, or as a matter of interest, passed votes in favour of this or that person, for remitting debts or granting away customs that were owing to the state. And at length, having kept the exchequer pure and clear from base informers, and yet having filled it with treasure, he made it appear that the state might be rich without oppressing the people. At first he excited feelings of dislike and irritation in some of his colleagues, but after a while they were well contented with him, since he was perfectly willing that they should cast all the odium on him, when they declined to gratify their friends with the public money, or to give dishonest judgments in passing their accounts; and when hard-pressed by suitors, they could readily answer it was impossible to do anything unless Cato would consent. On the last day of his office, he was honourably attended to his house by, almost all the people; but on the way he was informed that several powerful friends were in the treasury with Marcellus, using all their interest with him to pass a certain debt to the public revenue, as if it had been a gift. Marcellus had been one of Cato's friends from his childhood, and so long as Cato was with him, was one of the best of his colleagues in this office, but when alone, was unable to resist the importunity of suitors, and prone to do anybody a kindness. So Cato immediately turned back, and finding that Marcellus had yielded to pass the thing, he took the book, and while Marcellus silently stood by and looked on, struck it out. This done, he brought Marcellus out of the treasury, and took him home with him; who for all this, neither then, nor ever after, complained of him, but always continued his friendship and familiarity with him.
Cato, after he had laid down his office, yet did not cease to keep a watch upon the treasury. He had his servants who continually wrote out the details of the expenditure, and he himself kept always by him certain books, which contained the accounts of the revenue from Sylla's time to his own quaestorship, which he had bought for five talents.
He was always first at the senate, and went out last; and often, while the others were slowly collecting, he would sit and read by himself, holding his gown before his book. He was never once out of town when the senate was to meet. And when afterwards Pompey and his party, finding that he could never be either persuaded or compelled to favour their unjust designs, endeavoured to keep him from the senate, by engaging him in business for his friends, to plead their causes, or arbitrate in their differences, or the like, he quickly discovered the trick, and to defeat it, fairly told all his acquaintance that he would never meddle in any private business when the senate was assembled. Since it was not in the hope of gaining honour or riches, nor out of mere impulse, or by chance that he engaged himself in politics, but he undertook the service of the state as the proper business of honest man, and therefore he thought himself obliged to be as constant to his public duty as the bee to the honeycomb. To this end, he took care to have his friends and correspondents everywhere, to send him reports of the edicts, decrees, judgments, and all the important proceedings that passed in any of the provinces. Once when Clodius, the seditious orator, to promote his violent and revolutionary projects, traduced to the people some of the priests and priestesses (among whom Fabia, sister to Cicero's wife, Terentia, ran great danger), Cato having boldly interfered, and having made Clodius appear so infamous that he was forced to leave the town, was addressed, when it was over, by Cicero, who came to thank him for what he had done. "You must thank the commonwealth," said he, for whose sake alone he professed to do everything. Thus he gained a great and wonderful reputation; so that an advocate in a cause, where there was only one witness against him, told the judges they ought not to rely upon a single witness, though it were Cato himself. And it was a sort of proverb with many people, if any very unlikely and incredible thing were asserted, to say, they would not believe it, though Cato himself should affirm it. One day a debauched and sumptuous liver talking in the senate about frugality and temperance, Anaeus standing up, cried, "Who can endure this, sir, to have you feast like Crassus, build like Lucullus, and talk like Cato." So likewise those who were vicious and dissolute in their manners, yet affected to be grave and severe in their language, were in derision called Catos.