(1) باب اسْتِحْبَابِ النِّكَاحِ لِمَنْ تَاقَتْ نَفْسُهُ إِلَيْهِ وَوَجَدَ مُؤْنَةً وَاشْتِغَالِ مَنْ عَجَزَ عَنِ الْمُؤَنِ بِالصَّوْمِ
Sa'id b. al Musayyib heard Sa'd b. Abi Waqqas (Allah be pleased with him) saying that Uthman b. Maz'un decided to live in celibacy, but Allah's Messenger (ﷺ) forbade him to do so, and if he had permitted him, we would have got ourselves castrated.
Reference: Sahih Muslim 1402 c
In-book reference: Book 16, Hadith 9
USC-MSA web (English) reference(deprecated numbering scheme): Book 8, Hadith 3239