You shall judge of a man by his foes as well as by his friends.

Rivalry adds so much to the charms of one’s conquests.

Many need no other provocation to enmity than that they find themselves excelled.

Rivalry is the whetstone of talent.

Revenge may be wicked, but it’s natural.

Opposition may become sweet to a man when he has christened it persecution.

It is permitted to learn even from an enemy.

With the dead there is no rivalry.

Enemies are so stimulating.

The men of today are born to criticize; of Achilles they see only the heel.

When a coward sees a man he can beat, he becomes hungry for a fight.

It would seem that in history it’s never a tooth for a tooth, but a thousand, a hundred thousand for one.

Resentment kills a fool, and envy slays the simple.