What is a key teaching of Epictetus as noted in the Enchiridion?

The key teaching of Epictetus in the Enchiridion emphasizes the importance of focusing on what individuals can control. This Stoic principle is foundational to his philosophy, which teaches that many aspects of life are beyond our influence, such as the actions of others or external circumstances. Instead, individuals should concentrate their efforts and emotions on their own thoughts, reactions, and decisions, which are within their control.

By adopting this mindset, people can achieve a sense of peace and resilience. This approach reduces the anxiety and frustration that often arise from trying to manage things beyond one’s influence. The power lies in responding to challenges and maintaining one's character, regardless of outside events, which is a central tenet in Stoic thought. This understanding can lead to a more virtuous and fulfilling life, aligning with the broader goals of Stoicism, which seeks inner tranquility and ethical living.