This can be used as an analogy for other activities as well. For example, if you want a fresh baked loaf of bread, you'll gather flour, water, yeast and salt at a minimum and combine them in the right ratios, you'll mix and knead and let rise, you'll bake for the right amount of time. In the end, you'll reap a lovely browned perfectly baked loaf. You'd never expect to get bread from combining sausage and onions. You know that you have to add the right ingredients for the right outcome.
Character is the same way.
I recently came across this verse in my bible study time.
The truth is that you and I ARE producing something. We are never completely out of production, so WHAT is it that we are producing?