大般涅槃經義記 6.18

6.18

上來九空別破有無。第十「空空」，有、無雙遣。又前九空遣有、無性，第十遣其有、無別相，前有及無二俱是空，故曰空空。是義云何？因緣之法有無同體，以同體故，無法為有、有法為無，無為有故有即非有、有為無故無即非無，非有非無故曰空空。此前十門破遣情相以明空理。

The above nine emptinesses individually refute existence and non-existence. The tenth, 'emptiness of emptiness', dispels both existence and non-existence. Furthermore, the preceding nine emptinesses dispel the natures of existence and non-existence, while the tenth dispels the distinct marks of existence and non-existence; the preceding existence and non-existence are both empty, hence it is called 'emptiness of emptiness'. What is the meaning of this? Dharmas of causes and conditions share the same substance in terms of existence and non-existence; because they share the same substance, nonexistent dharmas are existent, and existent dharmas are nonexistent; because non-existence is existence, existence is precisely non-existence; because existence is non-existence, non-existence is precisely non-nonexistence; neither existent nor nonexistent, hence it is called 'emptiness of emptiness'. These preceding ten approaches refute and dispel mental marks in order to clarify the principle of emptiness.