To take refuge in the Buddha means to take refuge in the dharmas that constitute a buddha (a nonlearner). These consist of a buddha’s knowledge of the termination and nonarising [of the obscurations]. Together with the associated factors [of this knowledge], they consist of the five uncontaminated skandhas.
To take refuge in the sangha means [to take refuge] in the dharmas that constitute the sangha, which consists of [all] learners and nonlearners except for buddhas. It is by virtue of having attained their respective [dharmas] that the eight persons* are not separated from the path by [anyone], including gods. Therefore, they are called “sangha.” In other words, [the sangha] is represented by the five uncontaminated skandhas in the mind streams of said eight persons.
To take refuge in the dharma means [to take refuge] in the analytical cessation that is nirvana, that is, the two nirvanas [with and without remainder] of the noble ones.
* The eight persons are also known as “the four pairs of persons”—stream-enterers, once-returners, nonreturners, and arhats, each divided into approachers to, and abiders in, these states.
From Groundless Paths: The Prajnaparamita Sutras, The Ornament of Clear Realization, and Its Commentaries in the Tibetan Nyingma Tradition, translated by Karl Brunnholzl, page 85