I was recently reading Irving M. Bunim’s Ethics From Sinai and this is what he wrote:
“So can a human being be normally as docile as earth, as tranquil as still water, keeping whatever emotions and passions lie within him as dormant as a banked fire. Yet let a wind blow through him –a wind of envy, resentment, hatred, or thirst for revenge–and he may turn into a howling dust storm, a boundless flood, a ravaging fire.”
(Who is your enemy? The one who builds hatred against you. Someone who deserves your hatred in return.)* Jesus taught, “Love your enemy.” Instead of letting your enemy consume you with hatred and you consumed by yours, counteract by loving your enemy. If you see your enemy in need, assist them. Let your care and concern be the driving force of politeness that subdues the enemy’s evil inclination of hate. Learn to subdue your hatred and control it. Use weed killer on the blossoming flower of hate. In a human relation it won’t go away till both parties are reconciled. The seething of this seed of hatred must be controlled or it will end up controlling you.
*Irving M. Bunim
See also: When You’re Angry…
Perek IV Mishnah 24