When it departs, when it stays, or when it enjoys, bound up with the gunas, the deluded do not see it. Those with the eye of knowledge see it.
Explanation
Krishna is speaking about the embodied self (jīva), which takes up the senses and mind to experience the world. Whether it leaves the body, remains in it, or enjoys sense objects while joined with the gunas (the three strands of nature: sattva, rajas, tamas), the deluded cannot perceive it. Only those whose "eye of knowledge" (jñāna-cakṣus) has opened can see it. Commentators differ on whether "the one who departs" is the individual self alone or the self as one with the Supreme, but all agree that this seeing comes through wisdom, not the senses.