大方廣佛華嚴經隨疏演義鈔 36.61

36.61

疏「又上性無所有」下，別示諸因，先指經以明。性無所有者，即前偈自性無所有。內外雖異，皆是第一義空，故指前偈亦即此偈於此性也。既以第一義空為正因佛性，故性無所有即正因也。

Regarding the Commentary's statement, "Furthermore, above, 'nature has no existence,'" and so forth: this distinctively indicates the various causes, first pointing to the sūtra to clarify them. "Nature has no existence" refers to "its self-nature is non-existent" in the preceding verse. Although internal and external differ, both are the supreme-meaning emptiness; therefore, pointing to the preceding verse also refers to this verse's "regarding this nature." Since the supreme-meaning emptiness is taken as the direct-cause Buddha-nature, the non-existence of nature is precisely the direct cause.