Correct. A properly seasoned pan creates a barrier between the food and the iron. How do you know if your pan is properly seasoned? If you can't soak it overnight in water and/or air dry it without seeing rust, it's not seasoned properly.
Thank you! Turns out my skillet has lost some of its seasoning. Whether this is because or in spite of how we use it for spaghetti sauce so much remains to be seen.