(36) باب اشْتِرَاءِ التَّمْرِ بِالرُّطَبِ
it was narrated that Sa'd said:
"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." (DE)
Reference (DE): Sunan an-Nasa'i 4545 (DE)
In-book reference (DE): Book 44, Hadith 97 (DE)
English translation (DE): Vol. 5, Book 44, Hadith 4549 (DE)