From Sahih Bukhari (Hadith 4743):
Narrated Qais bin Ubad:Abu Dharr used to take an oath confirming that the Verse: 'These two opponents (believers, and disbelievers) dispute with each other about their Lord.' (22.19) was Revealed in connection with Hamza and his two companions and `Utbah and his two companions on the day when they went out to the battle of Badr
Reference: Bukhari 4743