Sertorius (16.4-16.5)

The strong man gave himself no end of trouble to no purpose, made the spectators laugh a good deal, and then gave up his attempt; but the weak man, in a trice and with no trouble, stripped his horse’s tail of its hair. Then Sertorius rose up and said Ye see, men of my allies, that perseverance is more efficacious than violence, and that many things which cannot be mastered when they stand together yield when one masters them little by little.

For irresistible is the force of continuity, by virtue of which advancing Time subdues and captures every power; and Time is a kindly ally for all who act as diligent attendants upon opportunity, but a most bitter enemy for all who urge matters on unseasonably.[*] By contriving from time to time such exhortations for the Barbarians, Sertorius taught them to watch for their opportunities.