大般涅槃經義記 4.180

4.180

文中有二：一明涅槃以之為船，佛為船師，正答上問；二「如人在海欲度」已下，乘說涅槃為之為風，彼涅槃中有證有教，證能濟度故說為船，教能擊發故說為風。

In the text there are two parts: first, explaining taking nirvāṇa as the boat and the Buddha as the ferryman, directly answering the question above; second, from "like a person in the ocean wishing to cross" below, in turn speaking of taking nirvāṇa as the wind. In that nirvāṇa there are realization and teaching: because realization can deliver across, it is spoken of as a boat; because teaching can stimulate and arouse, it is spoken of as the wind.