BhG 4.30-31

syntax

apare (others) niyatāhārāḥ (those who restrain from eating) prāṇeṣu (in the airs) prāṇān (airs) juhvati (they offer in sacrifice).
ete sarve api (indeed these all) yajña-vidaḥ (knowers of the sacrifice) yajña-kṣapita-kalmaṣāḥ (whose sins got destroyed by  sacrifice) yajña-śiṣṭāmṛta-bhujaḥ (those eating the nectar of remnants of sacrifices) sanātanaṁ brahma (to primeval spirit) yānti (they go).
he kuru-sattama (O the best among the Kurus!),
ayajñasya (of one who does not perform sacrifice) ayam lokaḥ (this world) na asti (it is not),
kutaḥ (how?) anyaḥ (other) [lokaḥ] (world).

grammar

apare	–	a-para 1n.3 m. – others, those later, different;
niyatāhārāḥ	–	niyata-āhāra 1n.3 m.; BV: yeṣām āhāro niyato ‘sti te – those who restrain from eating (from: ni-√yam – to hold back, PP niyata – held back; ā-√hṛ – to fetch, to carry near, āhāra – fetching, food, livelihood);
prāṇān	–	prāṇa 2n.3 m. – breaths, airs (from: pra-√an – to breath upwards → √prāṇ – to breath, to live);
prāṇeṣu	–	prāṇa 7n.3 m. – in breaths, in the airs (from: pra-√an – to breath upwards → √prāṇ – to breath, to live);
juhvati	–	√hu (to offer into fire) Praes. P 1v.3 – they offer in sacrifice;
sarve	–	sarva sn. 1n.3 m. – all;
api	–	av. – although, moreover, besides, even;
ete	–	etat sn. 1n.3 m. – these;
yajña-vidaḥ	–	yajña-vit 1n.3 m.; ye yajñān vetti te – those who know sacrifice (from: √yaj – to consecrate, to sacrifice, to worship, yajña – sacrifice, worship; √vid – to know, to understand, -vit – suffix: who knows);
yajña-kṣapita-kalmaṣāḥ	–	yajña-kṣapita-kalmaṣa 1n.3 m.; BV: yeṣāṁ yajñaiḥ kṣapitāni kalmaṣāni santi te – whose sins got destroyed by  sacrifice (from: √yaj – to consecrate, to sacrifice, to worship, yajña – sacrifice, worship; √kṣi – to destroy, caus. PP kṣapita – destroyed, diminished; karma+so – destroying good acts, kalmaṣa – dirt, stain, sin);

******

yajña-śiṣṭāmṛta-bhujaḥ	–	yajña-śiṣṭa-amṛta-bhuk 1n.3 m.; ye yajñasya śiṣṭam amṛta-rūpaṁ bhuñjanti te – those eating the nectar of remnants of sacrifices (from: √yaj – to consecrate, to sacrifice, to worship, yajña – sacrifice, worship, name of Viṣṇu; √śiṣ – to leave, PP śiṣṭa – left, remnants; √mṛ – to die; mṛta PP – dead, a-mṛta – not dead, eternal, nectar of immortality; √bhuj – to eat, to enjoy, bhuk – suffix: one who eats);
yānti	–	√yā (to go, to attain) Praes. P 1v.3 – they go, they attain;
brahma	–	brahman 2n.1 n. – spirit (from: √bṛh – to increase);
sanātanam	–	sanātana 2n.1 n. – eternal, primeval;
na		av. – not;
āyam	–	idam sn. 1n.1 m. – that;
lokaḥ	–	loka 1n.1 m. – world;
asti	–	√as (to be) Praes. P 1v.1 – it is;
ayajñasya	–	a-yajña 6n.1 m. – of one who does not perform sacrifice;
kutaḥ	–	av. – from where, how? (from: kim – what? indeclinable ablative with an ending -tas);
anyaḥ	–	anya sn. 1n.1 m. – other;
kuru-sattama	–	kuru-sattama 8n.1 m.; TP: kurūṇāṁ sattama ti – O the best among the Kurus (from: from: kuru – Kuru, Kurowie – descendants of Kuru; √as – to be, PPr sant – being, existing, true, the essence, superlative of: sat – sat-tara, sat-tama);

textual variants

yajña-kṣapita-kalmaṣāḥ → yajña-kṣapita-kilbiṣāḥ (whose faults got destroyed by sacrifice);
kuto ‘nyaḥ → kuto ‘nyat  (how the other?);

Śāṃkara

kiṃ ca—

apare niyatāhārā niyataḥ parimita āhāro yeṣāṃ te niyatāhārāḥ santaḥ, prāṇān vāyu-bhedān prāṇeṣv eva juhvati | yasya yasya vāyor jayaḥ kriyata itarān vāyu-bhedān tasmin tasmin juhvati, te tatra praviṣṭā iva bhavanti | sarve’py ete yajña-vido yajña-kṣapitakalmaṣā yajñair yathoktaiḥ kṣapito nāśitaḥ kalmaṣo yeṣāṃ te yajña-kṣapita-kalmaṣāḥ

evaṃ yathoktān yajñān nirvatrya —-

yajña-śiṣṭāmṛta-bhujo yajñānāṃ śiṣṭaṃ yajña-śiṣṭaṃ yajña-śiṣṭaṃ ca tad amṛtaṃ ca yajña-śiṣṭāmṛtaṃ tad bhuñjata iti yajña-śiṣṭāmṛta-bhujaḥ | yathoktān yajñān kṛtvā tac-chiṣṭena kālena yathā-vidhi-coditam annam amṛtākhyaṃ bhuñjate iti yajña-śiṣṭāmṛta-bhujo yānti gacchanti brahma sanātanaṃ cirantanaṃ mumukṣavaś cet | kālātikramāpekṣayeti sāmarthyād gamyate | nāyaṃ lokaḥ sarva-prāṇi-sādhāraṇo’py asti yathoktānāṃ yajñānām eko’pi yajño yasya nāsti so’yajñas tasya | kuto’nyo viśiṣṭa-sādhana-sādhyaḥ kuru-sattama

Rāmānuja

daivayajñaprabhṛtiprāṇāyāmaparyanteṣu karmayogabhedeṣu svasamīhiteṣu pravṛttā ete sarve „saha yajñaiḥ prajāḥ sṛṣṭvā” ityabhihitamahāyajñapūrvakanityanaimittikakarmarūpayajñavidaḥ tanniṣṭhāḥ tata eva kṣapitakalmaṣāḥ yajñaśiṣṭāmṛtena śarīradhāraṇaṃ kurvanta eva karmayoga vyāpṛtāḥ sanātanaṃ brahma yānti

ayajñasya mahāyajñādipūrvakanityamaimittikakarmarahitasya nāyaṃ lokaḥ na prākṛtalokaḥ, prākṛtalokasaṃbandhidharmārthakāmākhyaḥ puruṣārtho na sidhyati / kuta ito ‚nyo mokṣākhyaḥ puruṣārthaḥ? paramapuruṣārthatayā mokṣasya prastutatvāt taditarapuruṣārthaḥ ayaṃ lokaḥ iti nirdiśyate / sa hi prākṛtaḥ

Śrīdhara

tad evam uktānāṃ dvādaśānāṃ yajña-vidāṃ phalam āha sarve ‚pīti | yajñān vindanti labhanta iti yajña-vidaḥ | yajña-jñā iti vā | yajñaiḥ kṣayitaṃ nāśitaṃ kalmaṣaṃ yais te

yajña-śiṣṭāmṛta-bhuja iti | yajñān kṛtvā avaśiṣṭe kāle ‚niṣiddham annam amṛta-rūpaṃ bhuñjata iti tathā | te sanātanaṃ nityaṃ brahma jñāna-dvāreṇa prāpnuvanti | tad-akaraṇe doṣam āha nāyam iti | ayam alpa-sukho ‚pi manuṣya-loko ‚yajñasya yajñānuṣṭhāna-rahitasya nāsti | kuto ‚nyo bahu-sukhaḥ para-lokaḥ | ato yajñāḥ sarvathā kartavyā ity arthaḥ

Madhusūdana

tad evam uktānāṃ dvādaśadhā yajña-vidāṃ phalam āha sarve ‚pīti | yajñān vidanti jānanti vindanti labhante veti yajña-vido yajñānāṃ jñātāraḥ kartāraś ca | yajñaiḥ pūrvoktaiḥ kṣapitaṃ nāśitaṃ kalmaṣaṃ pāpaṃ yeṣāṃ te yajña-kṣapita-kalmaṣāḥ | yajñān kṛtvāvaśiṣṭe kāle ‚nnam amṛta-śabda-vācyaṃ bhuñjata iti yajña-śiṣṭāmṛta-bhujaḥ | te sarve ‚pi sattva-śuddhi-jñāna-prāpti-dvāreṇa yānti brahma sanātanaṃ nityaṃ saṃsārān mucyanta ity arthaḥ

evam anvaye guṇam uktvā vyatireke doṣam āha yejñety ardhena | uktānāṃ yajñānāṃ madhye ‚nyatamo ‚pi yajño yasya nāsti so ‚yajñas tasyāyam alpa-sukho ‚pi manuṣya-loko nāsti sarva-nindyatvāt | kuto ‚nyo viśiṣṭa-sādhana-sādhyaḥ para-loko he kuru-sattama

Viśvanātha

sarve ‚py ete yajña-vida ukta-lakṣaṇān yajñān vindamānāḥ santo jñāna-dvārā brahma yānti | atrānanusaṃhitaṃ phalam āha yajña-śiṣṭaṃ yajñāvaśiṣṭaṃ yad amṛtaṃ bhogaiśvarya-siddhy-ādikaṃ tad bhuñjata iti

tathānusaṃhitaṃ phalam āha brahma yāntīti | tad-akaraṇe pratyavāyam āha nāyam iti | ayam alpa-sukho manuṣa-loko ‚pi nāsti | kuto ‚nyo devādi-lokas tena prāptavya ity arthaḥ

Baladeva

ete khalv indirya-vijaya-kāmāḥ sarve ‚pīti yajña-vidaḥ | pūrvoktān devādi-yajñān vindamānā tair eva yajñaiḥ kṣapita-kalmaṣāḥ

ananusaṃhitaṃ phalam āha yajña-śiṣṭeti | yajña-śiṣṭaṃ yad amṛtam annādi bhogaiśvarya-siddhy-ādi ca tad-bhuñjānāḥ | anusaṃhitaṃ phalam āha yāntīti | tat-sādhyena jñānena brahmeti prāgvat