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.)
Hadith Referenceمشكوة المصابيح / كتاب البيوع / 2883
Hadith Gradingالألبانی:مُتَّفق عَلَيْهِ | زبیر علی زئی:متفق عليه
Hadith Takhrij´تحقيق و تخريج: محدث العصر حافظ زبير على زئي رحمه الله` «متفق عليه، رواه البخاري (2239) و مسلم (127/ 1604)»