Of all things nothing is so bad as the making of enemies.
Of all evils nothing is so hard to be borne as the triumph of an enemy.
Rejoice not over a fallen man--he may rise and you may fall.
Despise no enemy, however insignificant he may be--see how the shadow of the earth causes an eclipse of the moon, or how a midge brings a tear to the eye of a lion.
He who makes enemies shall have many a restless night.
He who has many enemies, let him expect a downfall.
p. 48
When anger is repressed by reason of inability to do immediate harm, it retires into the heart in the form of malice and breeds these vices--envy, triumph over the enemy's ill, repulsion of friendly approaches, contempt, slander, derision, personal violence, and injustice.