Responsibility

Epictetus discusses how humans have a responsibility to take care of certain things and do what's right. More poignant, though, is his delineation of responsibility. Epictetus spends a great amount of time in this work defining what is a responsibility for a human and what is beyond an individual's purview. He reasons that it is important to know what is strictly your responsibility so that one doesn't expend excess energy on things that they shouldn't—or can't—change.

Diligence

Epictetus stresses constant vigilance in everything we do as humans. In trying to be moral and ethical, it is easy to slip up and take actions that will harm ourselves or others in the long run. Once we understand our responsibility and the things for which we must care in this life, we must strive unceasingly to correct or improve upon those things. Epictetus's reasoning is that, if we are morally responsible for something, we should put as much effort and vigilance into it as humanly possible, because only then will we make the biggest impact we can possibly make.

Reason

One of Epictetus's final points is to teach us how to determine our responsibility and how to apply what we know to properly achieve our work. His belief is that reason and logic are the most important factors to this work. By applying reason, we can deduce what we are responsible for and how to work toward it, and because of this, Epictetus believes that reason is the best and most important trait that humanity has received.