大比丘三千威儀 1.67

1.67

不應說經有五事：一者人不敬三師；二者人犯戒；三者誹謗佛道；四者比丘問經不如法；五者不應為白衣說比丘戒經，得罪。

There are five matters when one should not expound the sūtras: first, when a person does not respect the three masters; second, when a person violates the precepts; third, when one slanders the Buddha's path; fourth, when a bhikṣu asks about the sūtras improperly; fifth, one must not expound the bhikṣu precept sūtra to white-robed laity—doing so incurs an offense.