四分律比丘含注戒本 2.796

2.796

佛在舍衛。比丘患瘡，膿血流出，污僧臥具。聽以大價衣覆瘡著涅槃僧。至白衣家，言「我有患」，當褰涅槃僧，以此覆瘡坐。六群便大作，比丘舉過，佛因制戒。

The Buddha was in Śrāvastī. A bhikṣu suffered from sores; pus and blood flowed out, staining the saṃgha's bedding. [The Buddha] allowed him to cover the sores with a high-priced cloth and wear his nivāsana over it. When going to a layperson's house, he was told to say, "I have an ailment," pull up his nivāsana, and sit with this covering the sores. The group-of-six bhikṣus then made [the cloth] oversized. The bhikṣus reported the fault, and the Buddha thereupon formulated the precept.