四分律行事鈔資持記 2.718

2.718

The eighth. (The Buddha was in Śrāvastī; a householder and his wife jointly discussed taking the price of a robe to buy a robe for Upananda; learning of this later, he went to their house and urged them to make it large, new, fine, and durable, incurring ridicule, and the rule was formulated accordingly.) In the name: "robe-price" refers to the cost of buying a robe.