The Wild Cocks and the Partridge
A bird seller put a beautiful partridge he bought among the wild cocks in his coop. The newly arrived partridge was deeply saddened because the wild cocks would not accept him among them and constantly pecked at him. The partridge thought "Because I am a stranger they do not want me among them and treat me unjustly." However, after a short while, he saw that the wild cocks were also mercilessly fighting amongst themselves in a bloody mess.
Seeing that the cocks pecked and beat even their own brothers, the partridge stopped grieving and relaxed. The partridge said "I am no longer sad; because this is their nature, they cannot live in peace even among themselves." Quarrelsome people who fight among themselves are naturally expected to treat others poorly. No friendship or kindness is expected from someone who is not at peace with themselves and their own kin.
One who has a fight with themselves cannot be at peace with others. The quarrelsome person shows no mercy even to their brother. No good comes to others from one who has a bad nature. One who has no peace within cannot offer peace outside.
One does not get offended by the words of a bad-natured person. A quarrelsome person causes unrest everywhere. Do not be surprised at one who cannot change their nature.