Narrated Sa'd bin Abi Waqqas: It was narrated that Sa'd bin Abi Waqqas said: The Messenger of Allah forbade 'Uthman to be celibate. If he had given him permission we would have castrated ourselves.
Narrated 'Aishah: It was narrated from 'Aishah that the Messenger of Allah forbade celibacy.
Narrated Samurah bin Jundab: It was narrated from Samurah bin Jundab that the Prophet forbade celibacy. Abu Abdur-Rahman said: Qatadah is more reliable and better preserves narrations than Ash'ath but the hadith of Ash'ath (here) appears to be the correct one. Allah, Most High, knows best.
Narrated Abu Salamah: It was narrated from Abu Salamah that Abu Hurairah said: I said: 'O Messenger of Allah, I am a young man and I fear hardship for myself, but I cannot afford to marry; should I castrate myself?' The Prophet turned away from him until he said it three times. Then the Prophet said: O Abu Hurairah, the pen is dried concerning what you are going to face, so (it is up to you whether) you castrate yourself or not. Abu Abdur-Rahman (An-Nasai) said: Al-Awzai did not hear this narration from Az-Zuhri, and this hadith is sahih, Yunus reported it from Az-Zuhri.
Narrated Sa'd bin Hisham: It was narrated from Sa'd bin Hisham that he came to the Mother of the Believers, 'Aishah. He said: I want to ask you about celibacy, what do you think about it? She said: Do not do that; have you not heard that Allah, the Mighty and Sublime, says: 'And indeed We sent Messengers before you, and made for them wives and offspring'? So do not be celibate.
Narrated Anas: It was narrated from Anas that there was a group of the Companions of the Prophet, one of whom said: I will not marry women. Another said: I will not eat meat. Another said: I will not sleep on a bed. Another said: I will fast and not break my fast. News of that reached the Messenger of Allah and he praised Allah then said: What is the matter with people who say such and such? But I pray and I sleep, I fast and I break my fast, and I marry women. Whoever turns away from my Sunnah is not of me.