As Paul starts Ephesians 3, he stops his thoughts at verse 2 and explores a tangent until verse 14. This tangent reveals his own heart in the midst of hardship. Hardship is one of the ways that we experience the fullness of salvation coming together in the wonder of how He works amidst suffering.
The book of Ephesians has a beautiful trajectory to it that starts with a rich theology found in the first three chapters: salvation from God’s point of view in chapter one, salvation from a human point of view in chapter two, and how those both come together in chapter three. Chapter four of Ephesians starts with the word “therefore” and reminds us that chapters 4-6, while practical, are based on the theology of chapters 1-3. We cannot live practically unless we know what we believe; in other words, doctrine shapes what we do.