四分律刪繁補闕行事鈔 1.57

1.57

若《四分》判文有限，則事不可通行，還用他部之文，以成他部之事。或二律之內，文義雙明，則無由取捨，便俱出正法，隨意采用。然行用正教，親自披閱，恐傳聞濫真故也！

If the Dharmaguptaka text provides a judgment with limited scope such that an affair cannot be universally applied, one returns to using the texts of other schools to accomplish the affairs of those other schools. Alternatively, if within two Vinayas both the text and meaning are equally clear, there is no basis for choosing between them; then both are set forth as true Dharma, to be adopted at will. However, when practicing and applying authentic teachings, one must peruse them in person, for fear that hearsay may corrupt the genuine!