حَدَّثَنَا مُحَمَّدُ بْنُ رُمْحٍ، أَنْبَأَنَا اللَّيْثُ بْنُ سَعْدٍ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، عَنْ رَسُولِ اللَّهِ ـ صلى الله عليه وسلم ـ قَالَ ‏"‏ لاَ تَبِيعُوا الثَّمَرَةَ حَتَّى يَبْدُوَ صَلاَحُهَا ‏"‏ ‏.‏ نَهَى الْبَائِعَ وَالْمُشْتَرِيَ ‏.‏

It was narrated from Ibn 'Umar that the Messenger of Allah (PBUH) said: "Do not sell fruits until they have ripened." And he forbade (both) the seller and the purchaser (to engage in such a transaction). Translation Not Available

Book Ref: Sunan Ibn Majah Book 12 Hadith 2214
Web Ref:  Sunan Ibn Majah Vol 3 Book 12 Hadith 2214