Good and evil are harnessed together to keep the wheel of life turning.
If only good existed, the wheel would not turn.
Yes, good is incapable of doing the job without a helping hand from evil. You might object that evil pulls in the opposite direction to good, but that is just the point – it has to do so!
Consider this simple gesture: when you want to cork or uncork a bottle, you use both hands working in opposite directions.
One pulls or pushes at the cork while the other exerts an opposing force on the bottle, and their combined effort enables you to insert or remove the cork. This collaboration between the two opposite forces happens every day before our very eyes, and we must give pause and meditate on it.