金光明最勝王經疏 3.185

3.185

贊曰：此牒依起身門，初喻、後法。空體遍常，又性本淨，故喻法身。應化無常，故喻電光。依起可知。

Commentary: This reiterates the gateway of the arising of the kāyas: first the metaphor, then the doctrine. The substance of space is pervasive and eternal, and its nature is fundamentally pure; hence it exemplifies the dharmakāya. The saṃbhoga and nirmāṇa kāyas are impermanent; hence they exemplify lightning and light. Their dependent arising is understood.