حَدَّثَنَا عَبْدُ اللَّهِ بْنُ مُحَمَّدٍ النُّفَيْلِيُّ، حَدَّثَنَا ابْنُ عُلَيَّةَ، عَنْ أَيُّوبَ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم نَهَى عَنْ بَيْعِ النَّخْلِ حَتَّى يَزْهُوَ وَعَنِ السُّنْبُلِ حَتَّى يَبْيَضَّ وَيَأْمَنَ الْعَاهَةَ نَهَى الْبَائِعَ وَالْمُشْتَرِيَ ‏.‏

Narrated Ibn 'Umar: The Messenger of Allah (PBUH) forbade selling palm-trees till the dates began to ripen, and ears of corn till they were white and were safe from blight, forbidding it both to the buyer and to the seller. Translation Not Available

Book Ref: Sunan Abi Dawud Book 23 Hadith 3368
Web Ref:  Sunan Abi Dawud Book 22 Hadith 3362