"From antiquity it has been said, 'Weapons are an inauspicious instrument, abhorred by the Way of Heaven, and to be used only when unavoidable. That is the Way of Heaven.'
How is this so? Bows and arrows, long swords, naginata - such are the weapons of the warrior, such are the instruments of ill fortune and inauspiciousness. Inasmuch as the Way of Heaven is the life-giving Way, then taking up arms to kill is truly unpropitious. To go against the Way of Heaven, verily, is abhorrent.
Be that as it may, it is said too that taking up arms to kill, when unavoidable, is also the Way of Heaven. Why must this be so?
Flowers blossom and greenery flourishes in the spring breeze, yet when the autumn frost comes, leaves fall and trees wither. Such is the decree of the Way of Heaven. There is a season to strike down what has come to fullness. People, too, will take an opportunity to do evil, and when that evil has come to fullness, it must be struck down. This is why it is said the use of weapons can also be the Way of Heaven. Because of the evil of one man, thousands may suffer. But by killing the evil of one man, thousands may live.
Does all this not show certainly that the sword that kills is the sword that gives life?"