'There is no time, sir, at which ties do not matter.'

From "Jeeves and the Impending Doom", the first story in Very Good, Jeeves! (p.266 in the Just Enough Jeeves anthology):

'I will tell you,' he said. 'I will also now reveal why I am staying in the pest-house, tutoring a kid who requires not education in the Greek and Latin languages, but a swift slosh on the base of the skull with a black-jack...

Horace, Aristotle, and Archilochus on a Boat...

From P.G. Wodehouse's The Girl on the Boat (p.108):

Nothing is more curious than the myriad ways in which reaction from an unfortunate love-affair manifests itself in various men. No two males behave in the same way under the spur of female fickleness. Archilochum, for instance, according to the Roman writer, proprio rabies armavit iambo. It is no good pretending out of politeness that you know what that means, so I will translate. Rabies – his grouch – armavit – armed – Archilochum – Archilochus – iambo – with the iambic – proprio – his own invention. In other words, when the poet Archilochus was handed his hat by the lady of his affections, he consoled himself by going off and writing satirical verse about her in a new metre which he had thought up immediately after leaving the house...

The verse quoted for the curious is 79 from Horace's Ars Poetica.

Later (p.187) we find:

 As I read over the last few chapters of this narrative, I see that I have been giving the reader rather too jumpy a time. To almost a painful degree I have excited his pity and terror; and, though that is what Aristotle says one ought to do, I feel that a little respite would not be out of order....

And then our man Horace makes another entrance in the final act (p.225):

 Jane Hubbard was a girl who by nature and training was well adapted to bear shocks. Her guiding motto in life was that helpful line of Horace – Aequam memento rebus in arduis servare mentem. (For the benefit of those who have not, like myself, enjoyed an expensive classical education, – memento – Take my tip – servare – preserve – aequam – an unruffled –  mentem – mind – rebus in arduis – in every crisis.)