He was narrating to them and said, "It was concerning me that this verse was revealed, and concerning a man with whom I had a dispute over a well. The Prophet ﷺ asked me, 'Do you have evidence?'I replied, 'No.'He said, 'Then let him take an oath.'I said, 'In that case he will swear falsely.'So the verse was revealed, 'Indeed, those who exchange the covenant of Allah...'" [Aal Imran 3:77]
فجاء الأشعث و
يحدثهم فقال في نزلت وفي رجل خاصمته في بئر فقال النبي ﷺ ألك بينة قلت لا قال فليحلف قلت إذا يحلف فنزلت {إن الذين يشترون بعهد الله} الآية