Power is based on faith. Whenever someone has faith in you, you have power over that person. This person believes that in following you they will gain something desirable.
We don't need authority to have power, but delegated authority can strengthen our power. When our authority comes from a higher power than ourselves, a person can believe in the higher power more than the one who has been delegated authority. Thus the one who is given delegated authority becomes a steward of that power.