We were given to eat, during the lifetime of Messenger of Allah 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 Messenger of Allah 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.
كُنَّا نُرْزَقُ تَمْرَ الْجَمْعِ عَلَى عَهْدِ رَسُولِ اللَّهِ ﷺ وَهُوَ الْخِلْطُ مِنَ التَّمْرِ فَكُنَّا نَبِيعُ صَاعَيْنِ بِصَاعٍ فَبَلَغَ ذَلِكَ رَسُولَ اللَّهِ ﷺ فَقَالَ لاَ صَاعَىْ تَمْرٍ بِصَاعٍ وَلاَ صَاعَىْ حِنْطَةٍ بِصَاعٍ وَلاَ دِرْهَمَ بِدِرْهَمَيْنِ