The uncrossable should not be sought to be crossed. That which the enemy would be able to recover should not be snatched from him. One should not try to dig at all if by digging one could get at the root of the thing for which one digs. One should never strike him whose head one would not cut off.
न तद्धरेद् यत् पुनराहरेत् परः। न तं हन्याद् यस्य शिरो न पातयेत्॥