حَدَّثَنَا عَبْدُ اللَّهِ بْنُ مُحَمَّدٍ النُّفَيْلِيُّ، حَدَّثَنَا سُفْيَانُ، عَنِ ابْنِ أَبِي نَجِيحٍ، عَنْ عَبْدِ اللَّهِ بْنِ كَثِيرٍ، عَنْ أَبِي الْمِنْهَالِ، عَنِ ابْنِ عَبَّاسٍ، قَالَ قَدِمَ رَسُولُ اللَّهِ صلى الله عليه وسلم وَهُمْ يُسْلِفُونَ فِي التَّمْرِ السَّنَةَ وَالسَّنَتَيْنِ وَالثَّلاَثَةَ فَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏"‏ مَنْ أَسْلَفَ فِي تَمْرٍ فَلْيُسْلِفْ فِي كَيْلٍ مَعْلُومٍ وَوَزْنٍ مَعْلُومٍ إِلَى أَجَلٍ مَعْلُومٍ ‏"‏ ‏.‏
Translation
Narrated Abdullah ibn AbuAwfa ibn AbuAwfa al-Aslami

We made a journey to Syria on an expedition along with the Messenger of Allah (ﷺ). The Nabateans of Syria came to us and we paid in advance to them (in a salam contract) in wheat and olive oil at a specified rate and for a specified time. He asked (by the people): you might have contracted with him who had these things in his possession? He replied: We did not ask them.