Speak no ill of a friend, nor even of an enemy. Pittacus of Mytilene
It is easier to forgive an Enemy than to forgive a Friend. William Blake
A proud monk needs no demon. He has turned into one, an enemy to himself. John Climacus
Bashfulness is an enemy to poverty. English Proverb
The obliging fool is worse than an enemy. Ukrainian Proverb
It is a real compliment that comes from an enemy. Persian Proverb