De Agricultura
Philo Judaeus
The works of Philo Judaeus, the contemporary of Josephus, volume 1. Yonge, C. D., translator. London: Henry G. Bohn, 1854.
For it is very difficult, as in the case of runners, for men, when they first begin to travel by the road which leads to piety, to keep their course straight onward without stumbling and without being out of breath; since there are innumerable hindrances to every human being,