Sahih Muslim 1595
Abu Sa'id (Allah be pleased with him) reported:
We were given to eat, during the lifetime of Allah's Messenger (ﷺ), dates of different qualities mixed together, and we used to sell two sa's of these for one sa, (of fine quality of dates). This reached Allah's Messenger (ﷺ), whereupon he said: There should be no exchange of two sa's of (inferior) dates for one sa (of fine dates) and two sa's of (inferior) wheat for one sa' of (fine) wheat. and one dirham for two dirharms.
حَدَّثَنِي إِسْحَاقُ بْنُ مَنْصُورٍ، حَدَّثَنَا عُبَيْدُ اللَّهِ بْنُ مُوسَى، عَنْ شَيْبَانَ، عَنْ يَحْيَى، عَنْ أَبِي سَلَمَةَ، عَنْ أَبِي سَعِيدٍ، قَالَ كُنَّا نُرْزَقُ تَمْرَ الْجَمْعِ عَلَى عَهْدِ رَسُولِ اللَّهِ صلى الله عليه وسلم وَهُوَ الْخِلْطُ مِنَ التَّمْرِ فَكُنَّا نَبِيعُ صَاعَيْنِ بِصَاعٍ فَبَلَغَ ذَلِكَ رَسُولَ اللَّهِ صلى الله عليه وسلم فَقَالَ ‏
"‏ لاَ صَاعَىْ تَمْرٍ بِصَاعٍ وَلاَ صَاعَىْ حِنْطَةٍ بِصَاعٍ وَلاَ دِرْهَمَ بِدِرْهَمَيْنِ ‏"‏ ‏.‏