華嚴經探玄記 1.42

1.42

九梁朝光宅寺雲法師立四乘教，謂如《法華》中，臨門三車即為三乘，四衢道中所授大白牛車即為第四乘，以臨門牛車亦同羊鹿俱不得故。若不爾者，長者宅內引諸子時云此三車只在門外，諸子出宅即應得車。如何出已，至本所指車所住處而不得故，後更索耶？故知是權同羊鹿也。以是大乘中權教方便說故。具釋如彼《法華疏》中。

Ninth, Dharma Master Yun of Guangzhai Temple under the Liang dynasty established a teaching of four vehicles. He held that, as in the Saddharmapuṇḍarīka Sūtra, the three carts [promised] at the threshold of the gate are the three vehicles, whereas the great white-ox cart conferred at the crossroads is the fourth vehicle, because the ox cart at the threshold was also not obtained, just like the goat and deer [carts]. Were this not so, when the elder inside the house enticed the children, he said that these three carts were right outside the gate; upon leaving the house, the children should have obtained the carts. How is it that after exiting and arriving at the place where the carts were originally indicated to be, they did not obtain them and later asked for them again? Therefore, one knows that this [promised cart] was provisional, just like the goat and deer [carts], because it was a provisional teaching and an upāya spoken within the Mahāyāna. The full explanation is as found in his Commentary on the Saddharmapuṇḍarīka Sūtra.