Philippians 4

I was reading about the Stoics, how they would seek an inner calm: "The Stoics did not seek to extinguish emotions, rather they sought to transform them by a resolute 'askēsis' which enables a person to develop clear judgment and inner calm."

This is different from the Bible's peace that passes understanding. Stoics used their own strength and understanding, but clear judgment is not just a highly developed reasoning skill, but reasoning based on what God says in His word. Inner calm is not emotional stability or a placid feeling concerning decisions, but a resting on the knowledge and the assurance that He's there and He's sovereign, and truly has all things in His control. Everything in life, people and circumstances, can make the soul unstable, frazzled, or uneasy, but there is a rest, a peace, when we bring to God all that make us anxious.