In plain words
Beings are unmanifest before birth, manifest in their middle state, and unmanifest again at death, Bharata. Why then lament?
Word for word
Beings have the unmanifest as their beginning, the manifest as their middle, O Bhārata, and the unmanifest as their end; what lament [is there] over that?
The commentators
Bhagavadgītābhāṣyam
कार्यकरणसङ्घातात्मकान्यपि भूतान्युद्दिश्य शोको न युक्तः कर्तुम् , यतः —
अव्यक्तादीनि अव्यक्तम् अदर्शनम् अनुपलब्धिः आदिः येषां भूतानां पुत्रमित्रादिकार्यकरणसङ्घातात्मकानां तानि अव्यक्तादीनि भूतानि प्रागुत्पत्तेः, उत्पन्नानि च प्राङ्मरणात् व्यक्तमध्यानि । अव्यक्तनिधनान्येव पुनः अव्यक्तम् अदर्शनं निधनं मरणं येषां तानि अव्यक्तनिधनानि । मरणादूर्ध्वमप्यव्यक्ततामेव प्रतिपद्यन्ते इत्यर्थः । तथा चोक्तम् — ‘अदर्शनादापतितः पुनश्चादर्शनं गतः । नासौ तव न तस्य त्वं वृथा का परिदेवना’(मो. ध. १७४ । १७) इति । तत्र का परिदेवना को वा प्रलापः अदृष्टदृष्टप्रनष्टभ्रान्तिभूतेषु भूतेष्वित्यर्थः ॥ २८ ॥
In plain words
Even taking beings to be nothing but this assembled bundle of body and senses, grief over them still does not hold up. Here is why:
Before a being is born -- before it shows up as a son, a friend, this whole bundle of body and faculties -- it was unseen. And after death, it goes back to being unseen. Only in between, from birth to death, does it appear at all. That's the whole shape of a life: unmanifest, then a brief manifest middle, then unmanifest again -- and it stays that way; death doesn't bring it back into view. As the old teaching puts it: 'He came from nowhere you could see, and has gone back to nowhere you can see. He was never really yours, and you were never really his -- so what is this grieving for?' So really -- what is there to mourn, what is there to cry over, in beings that were never more than unseen, then briefly seen, then gone again? The whole thing was just appearance.
Close to the Sanskrit
Even with reference to beings that are of the nature of an aggregate of the effect (body) and the instruments (senses), grief is not fitting to be made, because —
'Unmanifest-beginninged' [means]: 'unmanifest,' that is non-appearance, non-perception, is the beginning of which -- of which beings, composed of the aggregate of instruments and effects such as sons, friends, and so on -- those beings are 'unmanifest-beginninged,' before their origination, and having originated, until death, they are 'manifest-middled.' Again, 'unmanifest-ended' [means]: 'unmanifest,' that is non-appearance, non-perception, is the death, the demise, of which -- those are 'unmanifest-ended.' Meaning: after death also, they attain unmanifestness alone. And thus it has been said: 'Having arrived from non-appearance, and again gone to non-appearance -- he is not yours, nor are you his; why this vain lamentation?' [Mokṣadharma 174.17]. There, what lamentation, or what wailing, [could there be] -- meaning, with respect to beings that are [merely] unseen, [then] seen, [then] vanished, a delusion-appearance throughout?