成唯識論述記 7.221

7.221

述曰：「隨緣現」者，牒指頌也。顯非常起者，顯五識隨緣方能現起，非是常生，緣非恒故。第六雖亦隨緣方現，時緣恒具，故不言也。至下當知，由此五識多間斷故。

[The Commentary states:] 'Manifesting according to conditions' takes up and points to the verse. 'Shows that they do not arise constantly' shows that the five consciousnesses can only manifest according to conditions, and do not constantly arise, because conditions are not constant. Although the sixth also manifests only according to conditions, its conditions are constantly complete at all times, so it is not spoken of in this way. As will be known below, this is because these five consciousnesses have many interruptions.