It is narrated from Sayyiduna Sa'd bin Abi Waqqas (may Allah be pleased with him) that he intended to abstain from marriage (tabattul), so the Messenger of Allah (peace and blessings be upon him) forbade him from it. Sayyiduna Sa'd (may Allah be pleased with him) said: "Had he (peace and blessings be upon him) permitted it, we would have castrated ourselves."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 8282