Becoming the opponent means you should put yourself in an opponent's place and think from the opponent's point of view.

The only reason a warrior is alive is to fight, and the only reason a warrior fights is to win

To win any battle, you must fight as if you are already dead

When in a fight to the death, one wants to employ all one's weapons to the utmost. I must say that to die with one's sword still sheathed is most regrettable.