مُسْنَدُ أَحْمَدَ
Musnad Ahmad 1588
Musnad Abu Ishaq Sa'd bin Abi Waqqas
It was narrated that Sa"eed bin al-Musayyab said: I heard Sa"d bin Abi Waqqas say: The Messenger of Allah (ﷺ) refused to let "Uthman be celibate. if he had allowed him, we would have gotten castrated.
Musnad Ahmad 1588Sahih (Darussalam) [; al-Bukhari (5073) and Muslim (1402)]