法華論疏 3.356

3.356

釋中，諸佛法身自在身力者，此釋多寶於十方世界涌現及發聲歎佛之事。以法身遍一切處故，能於一切處有此功德。住持佛法，故為住持也。

In the explanation, "the bodily power of sovereignty of the dharmakāya of all Buddhas": this explains Prabhūtaratna's welling forth in the worlds of the ten directions and uttering a voice praising the Buddha. Because the dharmakāya pervades all places, it can have this merit in all places. Because it sustains the Buddha-Dharma, it is called sustaining.