YOU SAID:

To fight ones enemy, he must know that enemy

INTO JAPANESE

ものを戦うために敵、彼する必要があります知っている敵

BACK INTO ENGLISH

Know the enemy to fight that enemy, he must be

INTO JAPANESE

彼は敵と戦うために敵を知っています。

BACK INTO ENGLISH

Know the enemy to fight his enemies.

INTO JAPANESE

彼の敵を戦うために敵を知っています。

BACK INTO ENGLISH

Know the enemy to fight his enemies.