妙法蓮華經玄義 7.64

7.64

五、本神通者，亦是昔時所得無記化化禪，與本因時諸慈悲合，施化所作神通，駭動最初可度眾生，故言本神通也。

Fifth, the original supernormal powers: these are also the meditative states of morally neutral transformations attained in antiquity, conjoined with the various compassions and vows of the original causal stage; the supernormal powers wielded to dispense transformation startled and moved the sentient beings who could be saved at the very beginning. Therefore they are called the original supernormal powers.