Narrated Ibn 'Abbas:
The Prophet came (to Medina) and he told the people (regarding the payment of money in advance that they should pay it) for a known specified measure and a known specified weight and a known specified period.
حَدَّثَنَا قُتَيْبَةُ، حَدَّثَنَا سُفْيَانُ، عَنِ ابْنِ أَبِي نَجِيحٍ، عَنْ عَبْدِ اللَّهِ بْنِ كَثِيرٍ، عَنْ أَبِي الْمِنْهَالِ، قَالَ سَمِعْتُ ابْنَ عَبَّاسٍ ـ رضى الله عنهما ـ يَقُولُ قَدِمَ النَّبِيُّ صلى الله عليه وسلم وَقَالَ
" فِي كَيْلٍ مَعْلُومٍ وَوَزْنٍ مَعْلُومٍ إِلَى أَجَلٍ مَعْلُومٍ ".
• Sahih al-Bukhari, 2241
• Sahih al-Bukhari, Vol. 3, Book of Paid in Advance, Hadith 445
• Sahih al-Bukhari, Book of Paid in Advance, Hadith 445