This concept is similar to the idea of the self being like a wild horse that needs to be trained and tamed. The self is made up of various impulses, desires, and emotions that can sometimes become uncontrollable if left unchecked.
To tame the self, one must cultivate discipline, educate themselves on proper behavior, and sometimes punish or reward themselves accordingly. By doing so, the self can be guided towards positive and productive actions.
If one consistently portrays themselves as a person of determination and willpower, their self will begin to adopt those qualities as well. This can lead to a more focused and purposeful life.