It was narrated that 'Umar bin Khattab said:
"The last thing to be revealed was the Verse on usury but the Messenger of Allah ﷺ died before he had explained it to us. So give up usury (interest) and doubtful things."

حَدَّثَنَا نَصْرُ بْنُ عَلِيٍّ الْجَهْضَمِيُّ، حَدَّثَنَا خَالِدُ بْنُ الْحَارِثِ، حَدَّثَنَا سَعِيدٌ، عَنْ قَتَادَةَ، عَنْ سَعِيدِ بْنِ الْمُسَيَّبِ، عَنْ عُمَرَ بْنِ الْخَطَّابِ، قَالَ إِنَّ آخِرَ مَا نَزَلَتْ آيَةُ الرِّبَا وَإِنَّ رَسُولَ اللَّهِ ﷺ قُبِضَ وَلَمْ يُفَسِّرْهَا لَنَا فَدَعُوا الرِّبَا وَالرِّيبَةَ .