A passage from Seneca
Seneca, Letters to Lucilius Letter 68
✱
The mind is never right but when it is at peace within itself.
Related passages
✱
Men seek retreats for themselves, houses in the country, sea-shores, and mountains... But this is altogether a mark of the most common sort of men, for it is in thy power whenever thou shalt choose to retire into thyself.
✱
At dawn, when you have trouble getting out of bed, tell yourself: 'I have to go to work — as a human being.'
✱
Take care not to be Caesarified, or dyed with purple; for it does happen. Keep thyself then simple, good, pure, serious, free from affectation.