If you have assumed any character beyond your strength, you have both demeaned yourself ill in that and quitted one which you might have supported. - Epictetus

Don't you know that a good and excellent person does nothing for the sake of appearances, but only for the sake of having acted right?

Because I have no natural gifts, shall I on that account give up my discipline? Far be it from me! Epictetus will not be better than Socrates, but if only I am not worse, that suffices me. For I shall not be a Milo, either, and yet I do not neglect my body, nor a Croesus, and yet I do not neglect my property, nor, in a word, is there any other field in which we give up the appropriate discipline merely from despair of attaining the highest.

Sickness is a problem for the body, not the mind — unless the mind decides that it is a problem. Lameness, too, is the body's problem, not the mind's. Say this to yourself whatever the circumstance and you will find without fail that the problem pertains to something else, not to you.