Uthaym bin Kulayb narrates from his father, from his grandfather (may Allah be pleased with him), that he came to the Prophet (peace and blessings be upon him) and accepted Islam, and the Prophet (peace and blessings be upon him) ordered him: "Remove from yourself the hair of disbelief and get circumcised."
Abu Ahmad (Ibn Adi) said: As for Ibn Jurayj's saying in this chain, "I was informed from Uthaym bin Kulayb", it was in fact Ibrahim bin Abi Yahya who narrated it to him, and he concealed his name.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الأشربة والحد فيها / 17557