On the occasion of every accident that befalls you, remember to turn to yourself and inquire what power you have for turning it to use.
EpictetusConsider first the nature of the business in hand; then examine thy own nature, whether thou hast strength to undertake it.
EpictetusFreedom and happiness come from understanding - and working with - our limits. Begin at once a program of self-mastery. Stick with your purpose. Do not seek external approval. Do not worry about anything outside of your control. The only things you command are your thoughts and actions. We choose our response. Stop aspiring to be anyone other than your own best self: for that does fall within your control.
Epictetus