法華論疏 1.340

1.340

而言善堅實如來法輪者，妙光從八十劫已後乃至令八子堅固無上菩提，已無量時說法輪不壞，名為善堅實如來法輪。

As for stating "the Tathāgata's excellently firm and solid wheel of Dharma": Varaprabha, from eighty kalpas onward, up to causing the eight sons to become firm in unexcelled bodhi, preaching the wheel of Dharma for an immeasurable time without destruction, is called "the Tathāgata's excellently firm and solid wheel of Dharma."