維摩經略疏 2.31

2.31

「又十方至寶蓋中」，二、明現諸佛說法。若說依報必有能依，既有可化眾生必有應佛化導，故蓋中現佛及佛說法。以有四佛住於四土，皆名佛國。

From "Furthermore, the [buddhas] of the ten directions… within the jeweled canopy": second, clarifying the display of the buddhas preaching the Dharma. If one speaks of the dependent retribution, there must be that which relies on it; since there are sentient beings to be transformed, there must be response buddhas to transform and guide them; therefore, the buddhas and their preaching of the Dharma appear within the canopy. Because there are four buddhas dwelling in the four lands, all are named "buddha-lands."