大般涅槃經義記 5.257

5.257

第四為偈捨身之中，句別有六：一聞偈深思，處處書寫；二「即便」下欲為捨身；第三樹神問其所為，菩薩酬答；第四樹神問偈利益，菩薩為辯；五「我為」下明捨所為，并興廣願；六正捨身，空聲稱讚。

In the fourth [part], abandoning his body for the sake of the verse, there are six distinct clauses: first, hearing the verse, deeply contemplating it, and inscribing it everywhere; second, from "promptly" onward, wishing to abandon his body for it; third, the tree deity asks why he is doing this, and the bodhisattva replies; fourth, the tree deity asks about the benefit of the verse, and the bodhisattva explains it for him; fifth, from "I, for the sake of" onward, explains the purpose of the abandonment and gives rise to broad vows; sixth, he directly abandons his body, and a voice in the sky praises him.