大乘百法明門論開宗義決 1.45

1.45

言大乘者謂菩薩乘者。大乘之言通因及果。是佛菩薩大人乘故言菩薩乘。就因而論。菩薩乘此到佛地故。若言佛乘約果而說。一切諸佛本所乘故。簡異聲聞小人之乘。故舉菩薩而釋大乘。

Regarding "saying 'Mahāyāna' means the Bodhisattva Vehicle": The term Mahāyāna applies to both cause and fruit. It is the vehicle of great beings—buddhas and bodhisattvas—hence it is called the Bodhisattva Vehicle. Discussing it from the standpoint of the cause: the bodhisattva rides this to reach the Buddha stage. If one calls it the Buddha Vehicle, it is spoken with respect to the fruit, because it is that which all buddhas originally rode. To differentiate it from the vehicle of small persons, the śrāvakas, the bodhisattva is adduced to explain Mahāyāna.