First say to yourself what you would be; and then do what you have to do.

Epictetus (c. 55-c. 135 AD) Greek (Phrygian) Stoic philosopher [Ἐπίκτητος, Epíktētos]

The Discourses, ch. 23, “Concerning Such as Read and Dispute Ostentatiously” (c. AD 101-108)