Jabir b. Abdullah (Allah be pleased with them) is reported to have said that Messenger of Allah ﷺ forbade the sale of a heap of dates the weight of which is unknown in accordance with the known weight of dates.
أَخْبَرَهُ قَالَ سَمِعْتُ جَابِرَ بْنَ عَبْدِ اللَّهِ يَقُولُ نَهَى رَسُولُ اللَّهِ ﷺ عَنْ بَيْعِ الصُّبْرَةِ مِنَ التَّمْرِ لاَ يُعْلَمُ مَكِيلَتُهَا بِالْكَيْلِ الْمُسَمَّى مِنَ التَّمْرِ