8.20

परस्तस्मात्तु भावोऽन्योऽव्यक्तोऽव्यक्तात्सनातनः ।
यः स सर्वेषु भूतेषु नश्यत्सु न विनश्यति ॥

paras tasmāt tu bhāvo 'nyo 'vyakto 'vyaktāt sanātanaḥ
yaḥ sa sarveṣu bhūteṣu naśyatsu na vinaśyati

Kṛṣṇa (कृष्ण) continues. tu (तु) turns off the unmanifest of the night and names another.

The verse

But higher than that is another unmanifest being, eternal, beyond the unmanifest, which does not perish when all beings perish.

नेपालीमा

तर त्योभन्दा माथि अर्को अव्यक्त भाव छ, नित्य, अव्यक्तभन्दा पर, जुन सबै भूत नष्ट हुँदा पनि नष्ट हुँदैन।

Where it sits

The night-unmanifest of 8.18 is not the last word. There is a being beyond it, and the host's perishing does not carry that being away. 8.21 will call it the imperishable, the supreme goal, his own abode. 8.22 will say how it is reached.

Split: परः + तस्मात् + तु + भावः + अन्यः + अव्यक्तः + अव्यक्तात् + सनातनः + यः + सः + सर्वेषु + भूतेषु + नश्यत्सु + न + विनश्यति

paraḥ + tasmāt + tu + bhāvaḥ + anyaḥ + avyaktaḥ + avyaktāt + sanātanaḥ + yaḥ + saḥ + sarveṣu + bhūteṣu + naśyatsu + na + vinaśyati

Sanskrit, in depth

The words

देवनागरीWordGrammarSense
परःparaḥnominativehigher, beyond.
तस्मात्tasmātablativethan that.
तुtuindeclinablebut.
भावःbhāvaḥnominativea being, a state.
अन्यःanyaḥnominativeanother.
अव्यक्तःavyaktaḥnominativeunmanifest.
अव्यक्तात्avyaktātablativethan the unmanifest. The one of 8.18.
सनातनःsanātanaḥnominativeeternal, ancient.
यःyaḥnominativewhich.
सःsaḥnominativethat.
सर्वेषुsarveṣulocative pluralin all.
भूतेषुbhūteṣulocative pluralin beings, when beings.
नश्यत्सुnaśyatsulocative plural, present participleperishing. From naś (नश्).
नnaindeclinablenot.
विनश्यतिvinaśyatipresent, 3rd singularperishes. vi (वि) + naś (नश्).

The phrases

paraḥ tasmāt tu bhāvaḥ anyaḥ avyaktaḥ (परः तस्मात् तु भावः अन्यः अव्यक्तः) is the turn. But higher than that is another being, unmanifest. tasmāt (तस्मात्) points at the unmanifest they dissolve into at night. This one is other than that one. sanātanaḥ (सनातनः) agrees with bhāvaḥ (भावः). It does not share the day and the night.

avyaktāt (अव्यक्तात्) is a second ablative of comparison with paraḥ (परः). Beyond the unmanifest. The word avyakta (अव्यक्त) is used twice on purpose: once for this higher being, once for the one it is beyond.

yaḥ saḥ sarveṣu bhūteṣu naśyatsu na vinaśyati (यः सः सर्वेषु भूतेषु नश्यत्सु न विनश्यति) is what makes it other. Which, that one, does not perish when all beings are perishing. The locatives are the time. The main clause is na vinaśyati (न विनश्यति).

Sanskrit in this line

sarveṣu bhūteṣu naśyatsu (सर्वेषु भूतेषु नश्यत्सु) is a locative absolute. A noun and a participle, both locative, set the time or the condition, and they are not the subject of the main verb. "When all beings are perishing." The subject of na vinaśyati (न विनश्यति) is yaḥ saḥ (यः सः), the higher being. You met the shape at 1.20. Here the participle is plural because bhūteṣu (भूतेषु) is plural.

भावः + अन्यः + अव्यक्तः bhāvaḥ + anyaḥ + avyaktaḥ is recited bhāvo 'nyo 'vyaktaḥ (भावोऽन्योऽव्यक्तः). Three times, अः + अ aḥ + a becomes o (ओ) with an avagraha. Then अव्यक्तः + अव्यक्तात् avyaktaḥ + avyaktāt does it once more: avyakto 'vyaktāt (अव्यक्तोऽव्यक्तात्).

Say it back

Higher than the night's unmanifest, and it does not perish with the beings. If this avyaktaḥ (अव्यक्तः) is the same noun as avyaktāt (अव्यक्तात्), the verse's "another" is gone.