妙法蓮華經玄義 9.52

9.52

The four gates of the perfect teaching are also like this: responding to four kinds of capacities, therefore called four; all being spoken by the Buddha, therefore called one. Because entry into the contemplation of reality differs, they are called four; because the four contemplations head toward reality, they are called one. Taking the gates to name the principle, they are called four; responding to the gates with principle, they are called one. In this teaching, saṃsāra is immediately nirvāṇa, so the teaching is not narrow and small; defilements are immediately bodhi, so the practice is not narrow and small. Yet because this teaching and contemplation find it difficult to match the principle, the principle is called narrow and small. If one relies on the sūtra text, 'There is only one gate, and it is narrow and small', it specifically speaks of the gates of teaching and practice failing to match the principle, and hence says 'narrow and small'.