法華經義記 2.36

2.36

As for why it brings up the eight sons and eight hundred disciples to praise Varaprabha's loftiness of way and breadth of virtue, it has its own rationale. The earlier bringing up of the eight sons directly praises Varaprabha's loftiness of way to clarify that Mañjuśrī ought to reply, because Varaprabha of the past is now Mañjuśrī. The later bringing up of the most inferior person among the eight hundred disciples to praise Varaprabha's breadth of virtue clarifies that Maitreya ought to question, because the most inferior disciple of the past is now Maitreya. How is this known to be so? The great assembly had doubts, saying: "Maitreya is already a mahāsattva in the stage of succession, so he properly ought to answer; Mañjuśrī is not a mahāsattva in the stage of succession, so he properly ought to question. Why is it now that Maitreya instead questions Mañjuśrī?" Although Mañjuśrī answered Maitreya, since the assembly at that time had such a doubt, it is now explained: In the past, when Candrasūryapradīpa Buddha was in secular life, he had eight sons. These eight sons were originally Mañjuśrī's disciples. Mañjuśrī converted and guided the eight sons so that they all achieved the Buddha path. The last to achieve Buddhahood among the eight sons was named Dīpaṅkara. Dīpaṅkara Buddha is Dīpaṅkara (Dingguang); Dīpaṅkara Buddha was the teacher of Śākyamuni; Śākyamuni is again the teacher of Maitreya. Thus, Mañjuśrī is Śākyamuni's grand-teacher, and with respect to Maitreya, he is his great-grand-teacher. For this reason, Mañjuśrī ought to answer, and Maitreya ought to question.