We must realize that there is no way for us to overcome all our external foes. If we defeat one enemy, another always arises to take his place . . . How is it possible, Shantideva asks, to be free from all of our enemies who are as infinite as the expanse of space? Only be defeating our own anger can we overcome those who would harm us.
If we want to be protected while walking over rough and rocky ground, it is not realistic to think of covering the earth with leather. This would be impossible. Yet, if we had enough leather merely to cover the soles of our own feet, we would be able to walk anywhere. In a similar manner, it is far better simply to control our own anger than to try to defeat our external foes.
from Meaningful to Behold
by Geshe Kelsang Gyatso