Etymology矛 (모) [mo] - spear
盾 (순) [sun] - shield
性 (성) [seong] - nature, character, gender
There is no denying that our soul and body are in constant conflict and struggle.
We find a great contradiction in every person. Within the self-same individual are two opposing inclinations: the original mind that desires goodness and the evil mind that desires wickedness. They are engaged in a fierce battle. Any being possessing such a contradiction within itself is doomed to perish.
How could beings with a self-contradictory nature come into existence? If burdened by such a contradiction from its inception, human life would not have been able to arise. The contradiction, therefore, must have developed after the birth of the human race.
In order to ward off evil desires and follow good desires, we must overcome this ignorance and gain the ability to distinguish clearly between good and evil. Then we can take the path to the good life the original mind seeks.
To achieve personal perfection, you must first become master of yourself. In other words, you must gain self-control by learning to submit your body, and eliminate any contradictions between soul and body.