Narrated Ibn `Abbas:The Prophet (ﷺ) came to Medina and the people used to pay in advance the prices of fruits to be delivered within two to three years. The Prophet (ﷺ) said (to them), "Buy fruits by paying their prices in advance on condition that the fruits are to be delivered to you according to a fixed specified measure within a fixed specified period." Ibn Najih said, " ... by specified measure and specified weight."
حَدَّثَنَا أَبُو نُعَيْمٍ، حَدَّثَنَا سُفْيَانُ، عَنِ ابْنِ أَبِي نَجِيحٍ، عَنْ عَبْدِ اللَّهِ بْنِ كَثِيرٍ، عَنْ أَبِي الْمِنْهَالِ، عَنِ ابْنِ عَبَّاسٍ ـ رضى الله عنهما ـ قَالَ قَدِمَ النَّبِيُّ صلى الله عليه وسلم الْمَدِينَةَ وَهُمْ يُسْلِفُونَ فِي الثِّمَارِ السَّنَتَيْنِ وَالثَّلاَثَ، فَقَالَ " أَسْلِفُوا فِي الثِّمَارِ فِي كَيْلٍ مَعْلُومٍ إِلَى أَجَلٍ مَعْلُومٍ ". وَقَالَ عَبْدُ اللَّهِ بْنُ الْوَلِيدِ حَدَّثَنَا سُفْيَانُ، حَدَّثَنَا ابْنُ أَبِي نَجِيحٍ، وَقَالَ، " فِي كَيْلٍ مَعْلُومٍ وَوَزْنٍ مَعْلُومٍ ".
Bukhari
Sales in which a Price is paid for Goods to be Delivered Later (As-Salam) • Hadith 14