四分律行事鈔資持記 2.945

2.945

The ninth [rule]. (When the Buddha was in Śrāvastī, Udāyin whispered Dharma into the daughter-in-law's ear in front of the mother-in-law, because of which it was prohibited; later, exceptions were made for five or six words and for the presence of an intelligent man.) "Exceeding the limit" refers to beyond five or six words.