Sahih al-Bukhari 5073

Sa'id ibn al-Musayyab said, "I heard Sa'd ibn Abi Waqqas say, 'The Messenger of Allah, may Allah bless him and grant him peace, forbade celibacy to 'Uthman ibn Maz'un. If he had allowed that him to do that, we would have had ourselves castrated.'" Sa'id ibn al-Musayyab reported that he heard Sa'd ibn Abi Waqqas say "He (i.e. the Prophet, may Allah bless him and grant him peace) forbade 'Uthman ibn Maz'un to do that. If he had allowed him celibacy, we would have had ourselves castrated."