(17, 18) باب الْقِصَاصِ مِنَ الثَّنِيَّةِ
It was narrated that Anas said:
"Ar-Rubai broke the front tooth of a girls, and they asked them (her people) to forgive her, but they refused. They offered them blood money, but they refused. Then they went to the Prophet and he decreed relation. Anas Bin An-Nadr said: "O Messenger of Allah, will you break the front tooth of Ar-Rubai'? No, by the One Who sent you with the truth, it will not be broken!" He said: "O Anas, what Allah has decreed is retaliation." But the people agreed to forgive her. He (the Prophet) said: "There are among the slaves of Allah who, if they swear by Allah, Allah fulfills their oath."
Reference: Sunan an-Nasa'i 4757
In-book reference: Book 45, Hadith 52
English translation: Vol. 5, Book 45, Hadith 4761