The only teacher that's worth anything to you is your enemy.
We can learn even from our enemies.
There are people who pay attention to the weaknesses of their friends; that is to no avail. I have always closely watched and profited from the strengths of my adversaries.
It is good to be taught even by an enemy
It's right to learn, even from the enemy.
Fas est ab hoste doceri. One should learn even from one's enemies.
It is lawful to be taught by an enemy. Fas est ab hoste doceri.
It is from our enemies that we often gain excellent maxims, and are frequently surprised into reason by their mistakes.
You have so much to learn from your enemies.
I have always paid attention to the merits of my enemies, and found it an advantage.
