سنن ابن ماجه 599

It was narrated from 'Ali bin Abu Talib that:The Prophet said: "Whoever leaves an area the size of a hair on his body and does not cleanse it from sexual impurity, such and such will be done to him in the Fire." 'Ali said: "Because of that I am hostile towards my hair," and he used to shave his head

Rapporté par 'Ali bin Abu Talib : Le Prophète a dit : "Celui qui laisse une zone de la taille d'un cheveu sur son corps sans la purifier de l'impureté, il lui arrivera telle ou telle chose dans le Feu." 'Ali a dit : "À cause de cela, je suis sévère avec mes cheveux", et il avait l'habitude de se raser la tête