Sahih Muslim, 3405

Sa'id b. al-Musayyib reported:I heard Sa'd (b. Abi Waqqas) saying that the idea of 'Uthman b. Maz'un for living in celibacy was rejected (by the Holy Prophet), and if he had been given permission they would have got themselves castrated

Rapporté par Sa’id b. al-Musayyib : J’ai entendu Sa’d b. Abi Waqqas dire que le Prophète ﷺ a rejeté l’idée d’Uthman b. Maz’un de vivre dans le célibat, et que s’il lui avait donné la permission, ils se seraient fait castrer