مِشْكَاةُ الْمَصَابِيحِ
Mishkat al-Masabih 2883
Business Transactions
Payment in Advance and Pledge - Section 1
عَنِ ابْنِ عَبَّاسٍ قَالَ: قَدِمَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ الْمَدِينَةَ وَهُمْ يُسْلِفُونَ فِي الثِّمَارِ السَّنَةَ وَالسَّنَتَيْنِ وَالثَّلَاثِ فَقَالَ: «مَنْ سلف فِي شَيْءٍ فَلْيُسْلِفْ فِي كَيْلٍ مَعْلُومٍ وَوَزْنٍ مَعْلُوم إِلَى أجل مَعْلُوم»
Ibn 'Abbas said that when God’s Messenger came to Medina they were paying one, two and three years in advance for fruits, so he said, “Those who pay in advance for anything must do so for a specified measure and weight with a specified time fixed.” (Bukhari and Muslim.)
Mishkat al-Masabih, 2883مُتَّفق عَلَيْهِ (الألباني)