Hadith 771:44
Muhammad ibn Ja'far narrated to us, Shu'bah narrated to us, from 'Amr ibn Murrah, from Abu Hamzah, from Zayd ibn Arqam, who said: "The first to accept Islam with the Messenger of Allah, may Allah bless him and grant him peace, was Ali ibn Abi Talib." I mentioned that to an-Nakha'i, and he denied it and said: "Abu Bakr was the first to accept Islam with the Messenger of Allah, may Allah bless him and grant him peace."
حدثنا محمد بن جعفر، حدثنا شعبة، عن عمرو بن مرة، عن أبي حمزة، عن زيد بن أرقم قال: " أول من أسلم مع رسول الله صلى الله عليه وسلم علي بن أبي طالب " فذكرت ذلك للنخعي فأنكره وقال: " أبو بكر أول من أسلم مع رسول الله صلى الله عليه وسلم "