大毘盧遮那經供養次第法疏 2.28

2.28

此意言諸佛大力也。此大力是何等力耶？即如來十力，以一切力中最為大也。如來云何得此十力？謂從大慈而得此十力，故言此力從大慈發生也。四「次用已下乃至悉能普護之」，結大界真言門。次結大界真言。如佛所說更有無量持明，恐更有持明真言者等，以不結護，故破法事損持誦人，故設結界之法。由結界故，乃至諸持明亦不能破壞。猶比丘結界作法事，在界外比丘雖作法不能障破也。

This meaning speaks of the great power of all Buddhas. What kind of power is this great power? It is the Tathāgata's ten powers, which are the greatest among all powers. How did the Tathāgata obtain these ten powers? They were obtained from great compassion; hence it is said that this power arises from great compassion. Fourth, from "Next, by using..." onwards up to "are all able to protect universally," is the mantra gate of binding the great boundary. Next is the mantra for binding the great boundary. As the Buddha said, there are further immeasurable vidyādharas; fearing that other vidyādhara mantrins and the like, without boundary-protection having been bound, would disrupt the ritual actions and harm the reciter, the method of binding the boundary was established. Because of binding the boundary, even various vidyādharas cannot destroy it. Just as when bhikṣus bind a boundary to perform ritual acts, a bhikṣu outside the boundary, even if performing rites, cannot obstruct or disrupt them.