法華義疏 10.102

10.102

〈塔品〉明過去佛既方便示滅而實不滅，當知釋迦亦然。現在分身佛非實佛，則知釋迦亦爾，故能化顯能化也。今以菩薩數多及並已成就，則知釋迦成佛已久也。

The Apparition of the Jeweled Stūpa Chapter explains that since the past Buddha provisionally manifested extinction but in reality did not become extinct, one should know that Śākyamuni is also like this. Since the present emanated buddhas are not real buddhas, one then knows that Śākyamuni is also like this; hence the one who transforms reveals the one who transforms. Now, through the great number of bodhisattvas and their all having already been perfected, one then knows that Śākyamuni attained buddhahood long ago.