"The Messenger of Allah was asked about (buying) fresh dates with dried dates, and he said to those who were around him: 'Will fresh dates decrease (in weight or volume) when they dry out?" they said Yes,' so he forbade that." (Using translation from Nasāʾī 4545)  

سُئِلَ رَسُولُ اللهِ ﷺ عَنِ التَّمْرِ بِالرُّطَبِ فَقَالَ لِمَنْ حَوْلَهُ «أَيَنْقُصُ الرُّطَبُ إِذَا يَبِسَ؟» قَالُوا نَعَمْ فَنَهَى عَنْهُ  

"The Messenger of Allah was asked about (buying) said; 'Will fresh dates decrees (in weight or volume) when they dry out? 'They said 'yes so he forbade that" (Using translation from Nasāʾī 4546)  

سُئِلَ رَسُولُ اللهِ ﷺ عَنِ الرُّطَبِ بِالتَّمْرِ فَقَالَ «أَيَنْقُصُ إِذَا يَبِسَ؟» قَالَ نَعَمْ فَنَهَى عَنْهُ