Laudator Temporis Acti

Augustine, Sermons 66.5 (Patrologia Latina, vol. 38, col. 453 = Corpus Christianorum, Series Latina, vol. XLI A, p. 412; tr. Edmund Hill, with his note):

Bear the poor in mind; do what you haven't done yet. Believe me, you are not losing anything; in fact the only money you do lose is what you don't bring to the chariot.¹⁹ Now we have to pay back to the poor what you have offered—those of you who have offered anything! And we've got a much smaller sum here than you usually offer; shake off your sluggish reluctance, I have become a beggar for the beggars.

19. "The chariot," I guess, was a name for some sort of collecting box—perhaps an acolyte pulled it round the congregation. The Italian translator takes it literally, for the chariots that were raced in the circus, but he can only make sense of this by ignoring the negative "don't" in the sentence—perditis quod non fertis ad quadrigam. I have a recollection of coming across the word in an exactly similar context in one of his homilies on the psalms, but I cannot remember which one.

In mente habete pauperes: facite qui nondum fecistis: credite, non perditis; imo hoc solum perditis, quod non fertis ad quadrigam. Iam reddendum est pauperibus quod obtulistis, qui obtulistis: et multum minus habemus ad summam quam soletis offerre: excutite pigritiam. Ego factus sum mendicus mendicorum.

Not in Alexander Souter, A Glossary of Later Latin to 600 A.D. (Oxford: Oxford University Press, 1949). Cf. quadrigatus of a coin stamped with a quadriga.

Update: Thanks to Jim O'Donnell, who informs me that there are four more occurrences of quadriga in Augustine's works, none in the sermons and none with this sense.