I asked, "Messenger of Allah, what is the established practice regarding a man from the People of the Book who embraces Islam at the hands of another man?"He replied, "That man has the strongest claim to him in his life and in his death."
حدثنا أبو بكر بن أبي شيبة حدثنا وكيع عن عبد العزيز بن عمر عن عبد الله بن موهب قال سمعت
قلت يا رسول الله ما السنة في الرجل من أهل الكتاب يسلم على يدي الرجل قال هو أولى الناس بمحياه ومماته
[Hasan]. Abu Dawud narrated it in the Book of Inheritance, chapter on a man who embraces Islam at another man's hand, hadith no. 2918, from the hadith of Abdul-Aziz, through this chain. Hakim graded it sahih (2/219), but Dhahabi took issue with him. Bukhari mentioned it in his Sahih in suspended form, using the phrasing of doubt (Fath al-Bari 12/45). Shafii, Ahmad, Bukhari, Tirmidhi, and others graded it daif. Abu Zura Dimashqi said, "This is a hasan hadith with a connected chain. I have not seen anyone among the people of knowledge attribute it as a raised report." For more detail, refer to Nayl al-Maqsud. I have not found the argument of those who graded it daif to be convincing.