Bhagavad Gītā Chapter 8, Verse 17: Krishna to Arjuna — Akṣara-Brahma-Yoga

Bhāṣyakāra purports

• Śaṅkaraadvaita

  Brahman (brahmaṇaḥ, here Prajāpati-Virāj) undergoes a day of one thousand yugas (sahasra-yuga-paryantam) followed by an equal night — both rigidly bounded by kāla (time). Śaṅkara's commentary insists: because these cosmic cycles are kāla-pariccchinna (temporally delimited), all worlds within them, including Brahmaloka, are subject to punarāvṛtti (return). Only the one who realizes the timeless Brahman — beyond Prajāpati's counted days — escapes the wheel.

• Rāmānujaviśiṣṭādvaita

  Rāmānuja reads brahmaṇaḥ as caturmukha (four-faced Brahmā) whose very day-night rhythm is constituted by the saṃkalpa (will) of Bhagavān. The phrase mat-saṃkalpa-kṛta-ahorātra-vyavasthā (the day-night arrangement made by My will) frames the verse: even cosmic time is kainkarya-space (the Lord's sovereign ordering). Knowing this temporal architecture is thus knowledge of Bhagavān's sovereignty, a step toward prapatti (surrender) rather than mere calendrical scholarship.

• Madhvadvaita

  Madhva's commentary spans 8.17–8.19 as a unit establishing why reaching the Lord means no return. The 'thousands of yugas' is aneka-vācī (the word sahasra is interpreted as 'many,' not strictly one thousand), and the night here is the Mahā-Viṣṇu's rātri — supported by śruti: sā viśva-rūpasya rajanī. The dissolution intended is dvipararādha-pralaya (the great dissolution at two parārdha-lifetimes of Brahmā). Hari's realm alone stands beyond this kāla-cakra (cycle of time); jīvas (individual souls) who reach Him never re-enter Brahmā's counted days.

• Vallabhaśuddhādvaita

  Vallabha anchors the verse in the paurāṇika vākya (Purāṇic statement): catur-yuga-sahasraṃ tu brahmaṇo dinam ucyate. Brahmā's own day is kāla-pramita (measured by time), confirming that ā-brahma-bhuvanāt (up to Brahmaloka) all creation is within Kṛṣṇa's līlā-kāla (play-time). The twice-stated yuga-sahasra — for day and night — underscores that every creative and dissolving movement is Kṛṣṇa's prasāda-withdrawal and prasāda-gift. The devotee who sees Brahmā's day as Kṛṣṇa's breath rests in svarūpa-laya (dissolution into one's own essential nature) rather than fearing pralaya.

• Śrīdharabhakti

  Śrīdhara Svāmī (bhāṣya fully present) gives the richest calendrical gloss: one human year = one divine ahorātra (day-night); twelve thousand divine years = one catur-yuga; one thousand catur-yugas = Brahmā's one day. Those who know this are the true aho-rātra-vidaḥ — as opposed to those who track only candra-arka-gati (solar-lunar motion) and are alpa-darśin (of narrow vision). Maharloka and higher worlds are also encompassed by brahmaṇaḥ as an upalakṣaṇa (pointer-term). The verse grounds renunciation: even Brahmā's century is a measurable blink, so bhakti aimed at the unmeasured is the only rational investment.

• Madhusūdanaadvaita-bhakti

  Madhusūdana Sarasvatī reads the verse as answering 'why are even Brahmaloka's residents subject to return?' — because kāla-paricchinna-tva (time-delimitedness) is their condition. He echoes the paurāṇika vākya on catur-yuga-sahasra and adds, following Śrīdhara, that those who track only candra-arka are not true aho-rātra-vidaḥ due to svalpa-darśitva (littleness of vision). For Madhusūdana the yogin who truly knows Brahmā's day is the one whose heart is already anchored in Kṛṣṇa — the timeless witness behind all counted cycles — making jñāna and bhakti co-present in the very act of cosmic time-keeping.