涅槃經遊意 1.156

1.156

法短人長者，此少難見。且一往明三我人，同斷結惑，同入灰斷，未辨法有終極。今曰涅槃及前人法，明人壽等同太虛，正法終竟，滅盡故法短也。

As for "dharmas are short and persons are long," this is somewhat difficult to see. Tentatively, in terms of the three persons/selves, they equally cut off defilements and delusions, and equally enter the reduction to ashes and extinction, without yet discerning whether dharmas have a final limit. Now, speaking of nirvāṇa and the previously mentioned person and dharmas, it is explained that the person's lifespan is equal to vast space, while the true Dharma comes to an end and is utterly extinguished; hence dharmas are short.