The prohibition of selling fresh dates in exchange for dry dates except in the case of 'Araya
وَحَدَّثَنَا ابْنُ نُمَيْرٍ، حَدَّثَنَا أَبِي، حَدَّثَنَا عُبَيْدُ اللَّهِ، حَدَّثَنِي نَافِعٌ، عَنِ ابْنِ عُمَرَ، عَنْ زَيْدِ بْنِ ثَابِتٍ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم رَخَّصَ فِي الْعَرَايَا أَنْ تُبَاعَ بِخَرْصِهَا كَيْلاً .
Zaid b. Thabit (Allah be pleased with him) reported Allah's Messenger (ﷺ) granting concession in case of 'ariyya transactions and that implies selling of (dry dates for fresh dates) according to a measure.