Narrated Qais bin Ubad: 'Ali said, "I will be the first to kneel before the Beneficent on the '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.
Sahih al-Bukhari, Vol. 6, Book of Prophetic Commentary on the Qur'an, Hadith 268
Sahih al-Bukhari, Book of Prophetic Commentary on the Qur'an, Hadith 268