Sahih Muslim Book 10, Hadith Number 3907.

Chapter : How much land is to be spared when there is disagreement over the breadth of path.

Ibn ‘Abbas (Allah be pleased with them) reported that when Allah’s Messenger (may peace be upon him) 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).