(25) باب السَّلَمِ
Ibn 'Abbas (Allah be pleased with them) reported that when Allah's Messenger (ﷺ) came to (Medina) and the people were paying in advance (for the fruits, etc.), he said to them:
He who makes an advance payment should not make advance payment except for a specified measure and weight (and for a specified period).
Reference: Sahih Muslim 1604 b
In-book reference: Book 22, Hadith 158
USC-MSA web (English) reference(deprecated numbering scheme): Book 10, Hadith 3907