When you have decided that a thing ought to be done and are doing it, never avoid being seen doing it, though the many shall form an unfavorable opinion about it. For if it is not right to do it, avoid doing the thing; but if it is right, why are you afraid of those who shall find fault wrongly?
 Epictetus, Enchiridion (125). copy citation

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Author Epictetus
Source Enchiridion
Topic opinion fault
Date 125
Language English
Reference
Note Translated by George Long
Weblink https://en.wikisource.org/wiki/Encheiridion_of_Epictetus_(George_Long)

Context

“the thing, take care that the charm of it, and the pleasure, and the attraction of it shall not conquer you: but set on the other side the consideration how much better it is to be conscious that you have gained this victory. ==XXXV== When you have decided that a thing ought to be done and are doing it, never avoid being seen doing it, though the many shall form an unfavorable opinion about it. For if it is not right to do it, avoid doing the thing; but if it is right, why are you afraid of those who shall find fault wrongly? ==XXXVI== As the proposition it is either day or it is night is of great importance for the disjunctive argument, but for the conjunctive is of no value,Compare Discourses, i. 25, 11, etc. so in a symposium” source