The dark force Bitterness is probably better known as The Grudge. There is a little old Russian Tale about The Grudge:
A farmer finds a magic lamp. He rubs it and a genie appears. The genie grants him one wish. The farmer thinks about this for a while. Finally, he says, "My neighbour has a cow and I have none. I'd wish that his drops dead."
Don't hold a grudge against your fellow man
no matter what injustice or wrong he did
and do nothing at all by injurious practices
for your own sake.
Do no evil and no evil will come to you.
Stay away from wrong
and injustice will turn away from you.
