It is narrated from Sayyiduna Ali (may Allah be pleased with him) that the verse "These are two opposing parties who dispute concerning their Lord" [Surah al-Hajj: 19] was revealed about those who engaged in single combat (mubarazah) on the day of Badr, namely (from the side of the Muslims) Hamzah bin Abd al-Muttalib, Ali and Ubaydah bin al-Harith, and (from the side of the disbelievers) Utbah bin Rabi'ah, Shaybah bin Rabi'ah and al-Walid bin Utbah. Sayyiduna Ali (may Allah be pleased with him) said: "I will be the first person to fall upon his knees before Allah on the Day of Resurrection for the settlement of the dispute." With these narrations, this hadith is established as sahih (authentic) from Sayyiduna Ali (may Allah be pleased with him), just as it is established from Sayyiduna Abu Dharr al-Ghifari (may Allah be pleased with him), even though the two Shaykhs did not record it.