Ash'ath bin Salim says that during the caliphate of Abdullah bin Zubair (may Allah be pleased with him), I heard a man saying that I heard a man at the fair of 'Ukaz saying: "O people! Say La ilaha illallah, you will succeed." And behind him, another man was going, saying: "This person wants to turn you away from your gods." Later, it became known that they were the Prophet Muhammad (peace and blessings be upon him) and Abu Jahl.
Hadith Referenceمسند احمد / مسند الأنصار رضي الله عنهم / 23151