四分律行事鈔資持記 2.930

2.930

第六戒。（佛在曠野城，六群與俗誦經，聲高亂坐禪者，因制。）所以制此戒者，《多論》四意：初為異外道；二師資位別；三分別言章；四依實義，不在音聲。具斯四益，所以一制。

Sixth precept. (When the Buddha was in the city of Āṭavī, the ṣaḍvargikas recited sūtras together with laypeople, and the loud noise disturbed those sitting in meditation, occasioning the prohibition.) As for why this precept was prohibited, the Sarvāstivāda Vinaya Vibhāṣā gives four reasons: first, to differentiate from non-Buddhists; second, to distinguish the positions of master and disciple; third, to distinguish words and phrases; fourth, to rely on the real meaning and not reside in vocal sound. Endowed with these four benefits, it was therefore prohibited.