Sahih Bukhari Volume 6, Book 60, Hadith Number 268.

Narrated By Qais bin Ubad : ‘Ali said, “I will be the first to kneel before the Beneficent on the Day of Resurrection because of the dispute.” Qais said, “This Verse:

‘These two opponents (believers and disbelievers) dispute with each other about their Lord,’ (22.19) was revealed in connection with those who came out for the Battle of Badr, i.e. ‘Ali, Hamza, ‘Ubaida, Shaiba bin Rabi’a, ‘Utba bin Rabi’a and Al-Walid bin Utba.”