Da'ud bin Abi Hnd داود بن أبي هند · The Book on Blood Money

"A man bit the hand of another man. The man who was bitten pulled his hand out, causing two of his incisors (teeth) to fall out. They brought their case of the Prophet (ﷺ). So he said: "One of you bites his brother like the stallion bites? There is no blood-money for you.' So Allah Most High revealed: Wounds, equal for equal."