維摩經玄疏 2.26

2.26

如是三義，不縱不橫，為菩提種子。《涅槃經》云：「發心、畢竟二不別，如是二心前心難。自未得度先度人，是故敬禮初發心。」善識六即，則不混濫也。

These three meanings, neither vertical nor horizontal, are the seeds of bodhi. The Nirvāṇa Sūtra states: "The initial aspiration and the ultimate are not different; between these two minds, the prior mind is the difficult one. One who has not yet crossed over crosses others over first; therefore I pay homage to the initial aspiration." If one skillfully recognizes the six identities, there will be no confusion.