عَنِ اِبْنِ عَبَّاسٍ رَضِيَ اَللَّهُ عَنْهُمَا
قَالَ: قَدِمَ اَلنَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ اَلْمَدِينَةَ، وَهُمْ يُسْلِفُونَ فِي اَلثِّمَارِ اَلسَّنَةَ وَالسَّنَتَيْنِ، فَقَالَ: «مَنْ أَسْلَفَ فِي تَمْرٍ فَلْيُسْلِفْ فِي كَيْلٍ مَعْلُومٍ، وَوَزْنٍ مَعْلُومٍ، إِلَى أَجَلٍ مَعْلُومٍ»
When the Prophet (sallallahu alayhi wa sallam) came to al-Madinah, they were paying one and two years in advance for fruits. So he (sallallahu alayhi wa sallam) said: “Those who paid in advance for fruits must do so for a specified measurement and weight, and for a specified time.”.
Bulugh al-Maram 980, Book 7, Business Transactions, Hadith 91. 1 min read