大方廣佛華嚴經隨疏演義鈔 24.47

24.47

疏「故雖現形猶如水月」者，經云「佛真法身猶若虛空，應物現形如水中月。」此義佛佛平等，故結云「平等如虛空」。

Regarding the commentary's statement “Therefore, although manifesting form, it is like the moon in the water”: The sūtra says: “The Buddha's true dharmakāya is like empty space; responding to things, it manifests form like the moon in the water.” This meaning applies equally from Buddha to Buddha; hence it concludes: “equal like empty space”.