Sayyiduna al-Ash'ath bin Qays (may Allah be pleased with him) said: "This verse was revealed about me. I had a dispute with a man before the Messenger of Allah (peace and blessings be upon him), and then this verse was revealed: 'Indeed, those who sell the covenant of Allah and their oaths for a small price' [Surah Al Imran: 77]."
Hadith Referenceالمعجم الكبير للطبراني / باب الألف / 637