金光明最勝王經疏 2.13

2.13

問：四佛說壽，妙幢解生，何假釋迦重復陳說？答：菩提涅槃無上妙果，若不三說，餘不能解，故四佛創談、釋迦重說，陳如覆問喜見更彰。四佛即顯四德，三說即為三身，由此多因不唯一說。

Question: When the four Buddhas spoke of the life-span, Ruciraketu gave rise to understanding; why was it necessary for Śākyamuni to repeat the explanation? Answer: Bodhi and nirvāṇa are the unexcelled, marvelous fruits; if they are not explained three times, others cannot understand them. Therefore, the four Buddhas first proclaimed it, Śākyamuni repeated it, Kaundinya questioned it again, and Priyadarśana further made it clear. The four Buddhas manifested the four virtues, and the three explanations stood for the three bodies; on account of these many reasons, it was not spoken only once.