There is yet another aspect of self-discipline and that is the habit of thinking and of forgetting. This means on the one hand to be able to think of whatever one wishes to think of, and to continue to do so and to be able to hold that thought; and on the other hand to practice the forgetting of things, so that certain thoughts may not get a hold over one's mind; and in the same way to check thoughts of agitation, anger, depression, prejudice, hatred. This gives moral discipline and by doing so one becomes the master of one's mind.