法華玄論 9.158

9.158

答：有人言開無常顯常但在涅槃，餘二通兩教。今明三事互通，但開近顯遠明久已成佛，開無常顯常者此通久近。何以知之？證常有二種：一者久已證常、二今始證常，是故通也。開短顯長此復通上二義也。

Answer: Some say that opening the impermanent to reveal the permanent is only in the Nirvāṇa [Sūtra], while the other two apply to both teachings. I now clarify that the three matters mutually apply: opening the recent to reveal the long past clarifies that he attained buddhahood long ago; opening the impermanent to reveal the permanent applies to both the long past and the recent. How is this known? There are two kinds of realizing the permanent: first, having realized the permanent long ago; second, only now realizing the permanent; therefore it applies to both. Opening the short to reveal the long also applies to both of the above meanings.