法界次第初門 3.48

3.48

八、無為空。無為空者，無為法名無因緣，常不生不滅如虛空。今待有為，故說無為。若有為法不可得，則無無為之可著，故即是無為空。

Eighth: unconditioned emptiness. Unconditioned emptiness: unconditioned dharmas are named devoid of causes and conditions, permanently unproduced and unceasing like space. Now, in dependence on the conditioned, the unconditioned is spoken of. If conditioned dharmas are unapprehendable, there is no unconditioned to be attached to; thus it is itself unconditioned emptiness.