Sahih Muslim Book: 23, Hadith: 4168

وَحَدَّثَنَا سَلَمَةُ بْنُ شَبِيبٍ، حَدَّثَنَا الْحَسَنُ بْنُ أَعْيَنَ، حَدَّثَنَا مَعْقِلٌ، عَنْ أَبِي قَزَعَةَ، الْبَاهِلِيِّ عَنْ أَبِي نَضْرَةَ، عَنْ أَبِي سَعِيدٍ، قَالَ أُتِيَ رَسُولُ اللَّهِ صلى الله عليه وسلم بِتَمْرٍ فَقَالَ ‏”‏ مَا هَذَا التَّمْرُ مِنْ تَمْرِنَا ‏”‏ ‏.‏ فَقَالَ الرَّجُلُ يَا رَسُولَ اللَّهِ بِعْنَا تَمْرَنَا صَاعَيْنِ بِصَاعٍ مِنْ هَذَا ‏.‏ فَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏”‏ هَذَا الرِّبَا فَرُدُّوهُ ثُمَّ بِيعُوا تَمْرَنَا وَاشْتَرُوا لَنَا مِنْ هَذَا ‏”‏ ‏.‏ Abu Sa’id (Allah be pleased with him) reported:Dates were brought to Allah’s Messenger (may peace be upon him), and he said: These dates are not like our dates, whereupon a man said: We sold two sa’s of our dates (in order to get) one sa’, of these (fine dates), whereupon Allah’s Messenger (may peace be upon him) said: That is interest; so return (these dates of fine quality), and get your (inferior dates) ; then sell our dates (for money)...