四分律比丘含注戒本 2.67

2.67

The Buddha was in Śrāvastī. In front of a mother-in-law, Kālodayin whispered the Dharma into the ear of her daughter-in-law. Because the mother-in-law ridiculed and questioned it, bhikṣus reported the fault, and the Buddha on this account formulated the prohibition. Later, he permitted five or six phrases, or exceeding the limit in the presence of an intelligent man, and so forth.