佛頂尊勝陀羅尼經教跡義記 2.57

2.57

唐云千光明。解曰：千光明者諭化身，准此顯句釋三身。密字之中，先以廣辨，若以虛空清淨持業釋，云佛即虛空，謬之甚也。

In Chinese it means: "A thousand rays of light." The explanation states: The "thousand rays of light" are a metaphor for the nirmāṇakāya; by conforming to these explicit phrases, the trikāya is explained. Among the esoteric syllables, this was already broadly analyzed earlier; if one analyzes "pure like space" as a karmadhāraya compound, asserting that the Buddha is space itself, this is an extreme error.