Mens sana in corpore sano

The only road to a life of peace is virtue

"Mens sana in corpore sano": The phrase comes from Satire X of the Roman poet Juvenal (10.356). It is the first in a list of what is desirable in life:

English translation: You should pray for a healthy mind in a healthy body. Ask for a stout heart that has no fear of death, and deems length of days the least of Nature's gifts; that can endure any kind of toil; that knows neither wrath nor desire and thinks the woes and hard labors of Hercules better than the loves and banquets and downy cushions of Sardanapalus. What I commend to you, you can give to yourself; For assuredly, the only road to a life of peace is virtue.

In original Latin: orandum est ut sit mens sana in corpore sano. fortem posce animum mortis terrore carentem, qui spatium vitae extremum inter munera ponat naturae, qui ferre queat quoscumque labores, nesciat irasci, cupiat nihil et potiores Herculis aerumnas credat saevosque labores et venere et cenis et pluma Sardanapalli. monstro quod ipse tibi possis dare; semita certe tranquillae per virtutem patet unica vitae.

Source: https://en.wikipedia.org/wiki/Mens_sana_in_corpore_sano