In The Georgics Vergil offers the farmer some advice on what to do when the cold storms and long nights of winter keep him indoors. This gives him occasion to note that you can even do some of these things on holidays:
quippe etiam festis quaedam exercere diebus / fas et iura sinut (1.268–269)
Of course right even allows the performance of some tasks on holidays.
fas et iura, the former being natural right, the latter being legal right, I translate together as “right”. This lexicographical distinction was not strongly emphasized, as the present hendiadys shows, until the Christians, who invented the separation of church and state, which never existed in the pagan period, took over the government of the Roman Empire in the fourth and fifth centuries.
But the point here is not on the Christian invention of the idea of the separation of church and state, which modern ignorance and perversion of the idea, especially in the United States, where it has been subordinated to the concerns of political parties largely unconcerned with religion (or political philosophy for that matter), would make it impossible for most uneducated in its fourth century context to be willing to understand.
The point is the pagan wisdom about days of rest.
Macrobius in his Saturnalia comments here:
Vmbro negat eum pollui, qui opus uel ad deos pertinens sacrorumue causa fecisset, uel aliquid ad urgentem uitae utilitatem respiciens actitasset. Scaeuola denique consultus quid feriis agi liceret respondit, quod praetermissum noceret.
Umbro says that he is not polluted who has either done a work pertaining to the gods or for the purpose of religious rites, or has performed some act regarding a pressing need of life. Scaevola, moreover, when he was consulted as to what was permitted to be done on holidays, responded, “that which, if neglected, would be harmful.”
And Servius Danielis, like Macrobius a fourth-fifth century commentator on Vergil, says:
sed qui disciplinas pontificum interius agnouerunt, ea die festo sine piaculo dicunt posse fieri, quae supra terram sunt, uel quae omissa nocent, uel quae ad honorem deorum pertinent, et quidquid fieri sine institutione noui operis potest.
But those who have understood all the implications of the teachings of the pontifices [=pagan priests], say that those things can be done without piaculum [=taint of religious offense requiring expiation] on a holiday, which are supra terram [lit. “above earth”—I’m not totally sure what this means], or what, if omitted, are harmful, or what pertain to the honoring of the gods, and whatever is able to be done without the beginning of a new work.
It incurred a piaculum to do any work on a day of rest which would result in an individual gaining a competitive advantage, over and above what he needed in life, over his neighbor. The ancients, then, recognized the importance of the government to safeguard the observance of holidays against their known propensities in themselves to exploit competitive advantages in business that could be gained thereby.
Thanks, dear reader, should you ever find me, for being the gadfly of my discipline.