Mukhtasar Sahih Bukhari — Hadith 1829

The conqueror of Persia, Sayyiduna Sa’d bin Abi Waqqas (may Allah be pleased with him), used to say: The Noble Prophet (peace and blessings be upon him) forbade ‘Uthman bin Maz’un (may Allah be pleased with him) from abstaining from marriage; if he had permitted him, we would have become eunuchs.