大般涅槃經義記 5.195

5.195

就初心中，「心名無常」總以標舉，「何以」下釋，「以是」下結。釋中，初言「何以故」者徵前起後，「性是」已下舉後顯前心無常義。先開四門：性是一門，明其六識體性名異，故是無常；攀緣第二，明其六識緣境各別；相應第三，明其六識相應法界；分別第四，明其種種義門分別心非是常。

Within the first, the mind: 'The mind is called impermanent' generally indicates it; from 'Why' below explains it; from 'For this' below concludes it. In the explanation, first saying 'Why is that?' probes the preceding to introduce what follows; from 'Its nature is' onwards adduces what follows to reveal the preceding meaning that the mind is impermanent. First four gates are opened: the nature is one gate, clarifying that the essential natures of the six consciousnesses are different in name, and hence are impermanent; taking support on objects is the second, clarifying that the cognitive objects of the six consciousnesses are distinct; association is the third, clarifying that the six consciousnesses are associated with mental factors; discrimination is the fourth, clarifying by various theoretical gates of discrimination that the mind is not permanent.