His happiness, his delight, his very light are within: the freed one rests in Brahman.

Read from a brief, exact line rather than a developed argument.

What survives from Shankara here is short: happiness, delight, and the very light of knowing are within, in the Self alone, and such a yogin reaches nirvana in Brahman, the bliss that is Brahman, becoming Brahman while still living. The fuller Advaita case, that the veil of ignorance lifts and imagined duality dissolves, is genuinely his elsewhere in this text, and would fit naturally here. But because the record for this specific verse is this compressed, that fuller argument is not put in his mouth; what is offered is the short, exact claim the source itself makes.

Read as the self relished as one's own happiness, not extinguished.

Ramanuja reads brahma-nirvana positively, as the happiness of experiencing the self, and is careful that this must not be heard the way an alien school hears nirvana, as a blowing-out into nothing. What was earlier renounced, the enjoyable stuff of nature and the instruments that enjoy it, is not simply subtracted here; it is relocated. The very capacity for happiness that once reached toward objects now rests in the self, and through the self in the Lord who indwells it. Nothing of the person is emptied out; only where the happiness is permitted to rest has changed.

Read from what the surviving comment itself states, with identity-language held as extrapolation.

Madhva reads the inner light as, first and properly, the self-luminous Lord shining within the heart, since he alone shines without depending on anything else; every being carries an inward light, though in differing measure for each. His extant comment on this verse does not itself unpack become Brahman further; on his broader, well-known Dvaita position that the soul is never identical with the Lord even in liberation, one would expect him to read it as become situated in Brahman rather than as outright identity, but that specific reading is offered here as a conditional extension of his known theology, not as something this verse's own surviving words state.

Read from a terse surviving fragment, not a developed argument.

What survives of Abhinavagupta's comment here is a single brief gloss: happiness, delight, and light are within, depending on nothing outer, but in worldly dealing such a person appears as if dull, moving about as though without sense. On a Kashmir Shaiva reading more broadly, one would extend this to say the inward fullness is the freedom of consciousness recognizing itself, and the outward dullness is simply the stilling of ordinary reactivity. But that fuller extension is not in the surviving line, and is offered here only as a flagged, conditional reading, not as Abhinavagupta's own recorded word on this verse.

Read as inward from the very start, a homecoming rather than an achievement.

Sridhara is careful with each of the three inward marks in turn: the joy is not first sought outside and only later drawn in; the play is not first scattered and then gathered; the seeing is not first turned outward and then turned back. Each is an inward thing from the very start, and only one for whom all three are already inward like this is fit to be called a candidate for the peace of Brahman. He does not read this as a blanket warning against outer enjoyment; it describes a temperament whose center of gravity has already shifted inward, so that reaching Brahman is a homecoming, not a hardship.

Read as the stilling of imagined duality, a veil merely lifting.

Madhusudana gives the most technical account of the three marks. He is inwardly happy because his pleasure leans on no object, inner or outer; inwardly sporting because he has given up every outer means of pleasure; inwardly lit because his knowing rests on the Self and not the senses. In deep absorption sense objects do not appear to him at all, and in the active state, though they appear, he has settled that they are false and so gains no real pleasure from them. He calls the reward nirvana because it is the stilling of imagined duality, and reaching it, though it seems an attainment, is in truth only the lifting of a veil over what was ever already so.