"The Messenger of Allah forbade selling a heap of dried dates whose volume is unknown for known volume of dried dates," (Using translation from Nasāʾī 4547)
قَالَ سَمِعْتُ جَابِرَ بْنَ عَبْدِ اللَّهِ يَقُولُ «نَهَى رَسُولُ اللَّهِ ﷺ عَنْ بَيْعِ الصُّبْرَةِ مِنَ التَّمْرِ لَا يَعْلَمُ مَكِيلَهَا بِالْكَيْلِ الْمُسَمَّى مِنَ التَّمْرِ»