金光明經玄義 1.31

1.31

In differentiating the three Mahāyānas: if explained in terms of the Mahāyāna of the six perfections through cause and condition, this is still where three persons have different names but the same meaning. If explained in terms of the three persons jointly employing the unproduced to sever afflictions, the three persons jointly ride the one vehicle; this then is the vehicle within the shared teaching. If the three vehicles are attained in accord with the principle, and their substances and characteristics are distinctly different and not identical, this then is the vehicle within the distinct teaching. All three kinds are subsumed under the expedients for attaining the vehicle. In the Saddharmapuṇḍarīka-sūtra, the elephant vehicle is explained, adding to the three to make four: the goat, deer, and ox vehicles are subsumed under [the expedients for] attaining the vehicle, while the elephant vehicle is the principle-vehicle, just like the three vehicles explained here. In the Avataṃsaka-sūtra four vehicles are explained: the three vehicles are also subsumed under [the expedients for] attaining the vehicle, and the buddha vehicle is precisely the meaning of the three vehicles here.