四分律行事鈔資持記 2.752

2.752

十五。（佛在舍衛，徧行諸房，見故坐具狼藉因制揲故；六群違制，故立此戒。）

Fifteen. (The Buddha was in Śrāvastī. Walking through all the rooms, he saw old sitting mats strewn in disorder, and so prohibited it by requiring stitching patches of the old; the group-of-six violated the prohibition, so this precept was established.)