法華義疏 8.224

8.224

適緣不同，如釋迦六年苦行，彌勒即出家日成道也。而言十劫不成佛者，此欲待物緣熟在於十劫，故此時方成也。又有二益：未成道，令其供養生物福也；成道竟，受請說法生物慧也。

Adapting to conditions varies: as Śākyamuni practiced austerities for six years, while Maitreya will attain the path on the very day of his renunciation. As for saying that he did not attain Buddhahood for ten kalpas: this was wishing to wait until conditions with beings matured in the tenth kalpa, and therefore only at this time did he attain it. Moreover, there are two benefits: before attaining the path, causing them to make offerings generated beings' merit; after attaining the path, accepting their request to expound the Dharma generated beings' wisdom.