大方廣佛華嚴經隨疏演義鈔 33.56

33.56

疏「更約喻中」下，二約一異門。言「鏡是定一」者，謂如來藏唯一味故。「所現定異」者，生死緣差故。

Regarding the commentary's "Further, concerning the simile" and following: second, the approach of unity and difference. Regarding "the mirror is definitely one": this means that the tathāgatagarbha is solely of a single flavor. "What is manifested is definitely different": because the conditions of saṃsāra are distinct.