四分律行事鈔資持記 2.547

2.547

第八。（佛在羅閱祇，沓婆為知事，慈地次得惡房惡食，便令妹尼對僧以重謗故制。）名中。無根對下戒，重罪揀次篇。

The eighth. (When the Buddha was in Rājagṛha, Dabba was the manager of affairs; Mettiya in turn received an inferior room and inferior food, and thereupon had his sister, a bhikṣuṇī, make a grave slander before the saṃgha, hence [the Buddha] instituted the prohibition.) Regarding the name: "groundless" contrasts with the precept below; "grave offense" excludes the subsequent section.