Al-Lu'lu Wal-Marjan 1090 — The Book of Al-Qasama [The oath taken by fifty men (of the defendant) regarding a murder case when no evidence is available]

Anas Narrated from:

Ar-Rubai‘ (the paternal aunt of Anas bin Mâlik) broke the incisor tooth of a young Ansâri girl. Her family demanded the Qisâs [1] and they came to the Prophet صلى الله عليه وسلم who passed the judgment of Qisâs.Anas bin An-Nadr (the paternal uncle of Anas bin Mâlik) said, “O Allâh’s Messenger! By Allâh, her tooth will not be broken.” The Prophet صلى الله عليه وسلم said, “O Anas! (The law prescribed in) Allâh’s Book is Qisâs.” So (later on) the people (i.e. the relatives of the girl) gave up their claim and accepted a compensation. On that Allâh's Messenger ﷺ said, "Some of Allâh's worshippers are such that if they take an oath, Allâh will fulfil it for them." ( Sahîh Al-Bukhârî, Hadîth No. 135, Vol. 6)