Sahih al-Bukhari, 1817

Narrated `Abdur-Rahman bin Abu Layla:(Reporting the speech of Ka`b bin Ujra) Allah's Messenger (ﷺ) saw him (i.e. Ka`b) while the lice were falling on his face. He asked (him), "Have your lice troubled you?" He replied in the affirmative. So, he ordered him to get his head shaved while he was at Al-Hudaibiya. At that time they were not permitted to finish their Ihram, and were still hoping to enter Mecca. So, Allah revealed the verses of Al-Fidya. Allah's Messenger (ﷺ) ordered him to feed six poor persons with one Faraq of food or to slaughter one sheep (as a sacrifice) or to fast for three days

Rapporté par ‘Abdur-Rahman ibn Abu Layla : (Rapportant les paroles de Ka‘b ibn ‘Umra) Le Messager d’Allah (ﷺ) l’a vu (c’est-à-dire Ka‘b) alors que les poux tombaient sur son visage. Il lui a demandé : « Les poux t’ont-ils causé des soucis ? » Il a répondu oui. Alors, il lui a ordonné de se raser la tête alors qu’il était à Al-Houdaybiya. À ce moment-là, ils n’avaient pas la permission de terminer leur Ihram et espéraient encore entrer à La Mecque. Allah a alors révélé les versets concernant la Fidya. Le Messager d’Allah (ﷺ) lui a ordonné de nourrir six pauvres avec un Faraq de nourriture, ou de sacrifier un mouton, ou de jeûner trois jours