肇論新疏 3.199

3.199

是以論稱出有無者，良以有無之數止乎六境之內，六境之內非涅槃之宅，故借出以祛（遣）之。

"Therefore, when the treatise speaks of transcending existence and non-existence, it is truly because the categories of existence and non-existence are confined within the six sense realms. Within the six sense realms is not the abode of nirvāṇa; hence the term 'transcending' is borrowed to dispel them.