Letters 51.10

Therefore, a man occupied with such reflections should choose an austere and pure dwelling-place. The spirit is weakened by surroundings that are too pleasant, and without a doubt one’s place of residence can contribute towards impairing its vigour. Animals whose hoofs are hardened on rough ground can travel any road; but when they are fattened on soft marshy meadows their hoofs are soon worn out. The bravest soldier comes from rock-ribbed regions; but the town-bred and the home-bred are sluggish in action. The hand which turns from the plough to the sword never objects to toil; but your sleek and well-dressed dandy quails at the first cloud of dust.

Seneca, Letters to Lucilius 51.10, translated by Richard Mott Gummere