維摩經玄疏 5.142

5.142

八、類通三種涅槃者：一，性淨涅槃；二，圓淨涅槃；三，方便淨涅槃。圓淨之名，未見經文，有地論師云：「『方便淨涅槃』，出經文義，立應化涅槃，以為三涅槃也。若取義『便』，以圓淨為便；若取『方便』，方便淨為便。」今明真性解脫，即性淨涅槃；實慧解脫，即圓淨涅槃；方便解脫，即方便淨涅槃也。

Eighth, analogously correlating the three kinds of nirvāṇa: first, naturally pure nirvāṇa; second, completely pure nirvāṇa; third, expediently pure nirvāṇa. The name 'completely pure' is not yet seen in the sūtra text. A master of the Daśabhūmika said: ''Expediently pure nirvāṇa' is derived from the meaning of the sūtra text, establishing responsive and transformed nirvāṇa to make the three nirvāṇas. If one takes the convenient sense, completely pure is convenient; if one takes 'expedient means', expediently pure is convenient.' Now we explain that the liberation of the true nature is naturally pure nirvāṇa; the liberation of real wisdom is completely pure nirvāṇa; the liberation of expedient means is expediently pure nirvāṇa.