James is not telling you to stop making plans. He's confronting the posture of planning without God — the entrepreneur who maps out the next three years with full confidence in their own ability to execute.
Presumption is planning with a closed fist. Wisdom is planning with an open hand.
The difference shows up in how you respond when plans fall through. The presumptuous entrepreneur panics or doubles down. The wise entrepreneur asks: "Lord, what are you redirecting me toward?"
Proverbs 16:9 is not a warning against planning — it's a comfort. Plan your course. Make it clear and specific. Then hold it loosely, knowing God is in the business of course-correcting people who are willing to be led.