What is night for all beings, in that the self-controlled one is awake; in what beings are awake, that is night for the seeing sage

The inversion of values: niśā (night) for sarva-bhūtāni (all beings) is jāgarti (awake) for saṃyamin (the self-controlled). What people ignore (spiritual reality) is where the sage is alert.

Conversely: yasyām jāgrati bhūtāni (where beings are awake — material world), sā niśā (that is night) paśyataḥ muneḥ (for the seeing sage).

The muni (silent sage) “sees” (paśyataḥ) what others do not see. His categories of day/night are inverted because his source of light is different.