成唯識論演祕 1.90

1.90

略為二釋：一云：報、化二身名為善逝，體通二義。若善逝即體，體屬報、化；善逝之體，體屬法身。慈尊繼襲佛之寶位，是真佛子，名彼體生。二云：善逝及體總是法身，慈氏之智要緣於如而方得生，智因彼起名彼所生。天親自指身及同學名為我等，師即無著菩薩是也。

Briefly, there are two interpretations: One says: The saṃbhogakāya and nirmāṇakāya are called the Sugata, and "substance" applies to two meanings: if the Sugata is identical to the substance, the substance belongs to the saṃbhogakāya and nirmāṇakāya; if it is the substance of the Sugata, the substance belongs to the dharmakāya. The Venerable Maitreya inherits the precious throne of the Buddha and is a true son of the Buddha, so he is called born of that substance. The second says: Both the Sugata and the substance are the dharmakāya; the wisdom of Maitreya must take Suchness as its object before it can arise, and since wisdom arises on that basis, it is called born of that. Vasubandhu refers to himself and his fellow students as "we," and their master was Bodhisattva Asaṅga.