Epictetus, Discourses 2.15.1

Chapter 15: On those who cling stubbornly to their judgments. There are some who when they hear these precepts—that a man must be steadfast, and that the will is by nature a free thing and not subject to compulsion, whereas all else is subject to hindrance and compulsion, being in bondage and dependence—imagine that they must abide without swerving by every judgement that they have formed.…