Similar quotesMoney couldn't buy you friends, but you get a better class of enemy.
Spike Milligan 
Never interrupt your enemy when he is making a mistake.
Napoleon 
You must not fight too often with one enemy, or you will teach him all your tricks of war.
Napoleon 
The best weapon against an enemy is another enemy.
Friedrich Nietzsche 
The weak can never forgive. Forgiveness is the attribute of the strong.
Mahatma Gandhi 