The instruction here has a sequence, and skipping it is why the verse gets misapplied. It isn’t “find peace, then pray” — it’s pray first, specifically, with thanksgiving, and peace follows as the result, not the prerequisite. “Which surpasses all understanding” isn’t a vague compliment either; the next word is “guard,” a military term for a garrison standing watch at a border. Paul is picturing peace as an active defense stationed around your mind, not a feeling you generate by trying hard to relax. You don’t need to feel calm before you pray. The calm, if it comes, comes after.