It said that internally the mind has adversity and favourable circumstances -- relying on the princple as the model one then learns the edifying teaching. Externally actions are undertaken – one must guard the body and speech and so then one depends on the practical teaching. Thus, one who violates the edifying teachings only receives a single retribution on the path of karma. The one who violates the practical teachings doubly increases the crime of [violating] the sacred discipline.
Daoxuan 道宣 (596-667) is hailed as a great vinaya master of the Tang Dynasty. He wrote an extensive commentary on the vinaya that consolidated various interpretations as well as accommodating Śrāvaka precepts in an entirely Bodhisattva-based system of ethics. He made a distinction between edifying teachings and practical teachings. The former concern the internal mind, the later two concern body and speech or external activities. He was quite firm in his teaching that discipline is indeed the foundation of Buddhist practise.