大方廣佛華嚴經隨疏演義鈔 43.51

43.51

疏「大分深義所謂空故」者，即《十二門論》，但改彼「也」字為「故」字耳。

Regarding the Commentary's line "The vast and deep meaning is because it is the so-called emptiness": this comes from the Dvādaśanikāya-śāstra; it merely changed that text's character yě 也 into the character gù 故.