Sayyiduna Ali (may Allah be pleased with him) said: A sheet was found in the sword of the Prophet (peace and blessings be upon him), in which was written: "Whoever enters Islam uncircumcised is not to be left until he is circumcised, even if he is 80 years old."
Only the members of the Prophet's household (Ahl al-Bayt) (peace be upon them) narrate this hadith with this chain.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الأشربة والحد فيها / 17558