“Nature herself, indeed, seems to have given music to us as a benefit, to enable us to endure labors with greater facility, for musical sounds cheer even the rower; and it is not only in those works in which the efforts of many, while some pleasing voice leads them, conspire together that music is of avail, but the toil even of people at work by themselves finds itself soothed by song, however rude.”

H. E. Butler's translation:
Indeed nature itself seems to have given music as a boon to men to lighten the strain of labour: even the rower in the galleys is cheered to effort by song. Nor is this function of music confined to cases where the efforts of a number are given union by the sound of some sweet voice that sets the tune, but even solitary workers find solace at their toil in artless song.
Book I, Chapter X, 16
De Institutione Oratoria (c. 95 AD)
Original: (la) Atque eam natura ipsa videtur ad tolerandos facilius labores velut muneri nobis dedisse, si quidem et remigem cantus hortatur; nec solum in iis operibus in quibus plurium conatus praeeunte aliqua iucunda voce conspirat, sed etiam singulorum fatigatio quamlibet se rudi modulatione solatur.