BhG 3.28

syntax

he mahā-bāho (O mighty-armed one!),
tu (but) guṇa-karma-vibhāgayoḥ (of guṇa division and of activity division) tattva-vit (who knows the truth) matvā (after thinking):
guṇāḥ (guṇas) guṇeṣu (in guṇas) vartante iti (they act)
[saḥ] (he) na sajjate (he is not attached).

grammar

tattva-vit	–	tattva-vit 1n.1 m.; yaḥ tattvaṁ vetti saḥ – who knows the truth (from: tat – that, abst. tat-tva – truth, reality; √vid – to know, to understand, -vit – suffix: who knows);
tu	–	av. – but, then, or, and;
mahā-bāho	–	mahā-bāhu 8n.1 m.; BV: yasya bāhū mahāntau staḥ saḥ – O you who have mighty arms (from: √mah – to magnify, mahant – great; √baṁh – to grow, to increase, bāhu – the arm);
guṇa-karma-vibhāgayoḥ	–	guṇa-karma-vibhāga 6n.2 m.; TP: guṇānāṁ ca karmaṇāṁ ca vibhāgayor iti – of two divisions: guṇa and ctivity (from: √grah – to take, guṇa – quality, virtue, thread; √kṛ – to do, karman – activity and its result; vi-√bhāj – to divide, to separate; vi-bhāga – share, portion, division);
guṇāḥ	–	guṇa 1n.3 m. – qualities, virtues, threads (from: √grah – to take);
guṇeṣu	–	guṇa 7n.3 m. – in qualities, virtues, threads (from: √grah – to take);
vartante	–	√vṛt (to move, to happen, to act) Praes. Ā 1v.3 – they act;
iti	–	av. – thus (used to close the quotation);
matvā	–	√man (to think) absol. – after thinking;
na	–	av. – not;
sajjate	–	√sañj (to attach, to stick, to embrace) Praes Ā 1v.1 – he is attached;

textual variants

guṇa-karma-vibhāgayoḥ → guṇa-karma-vibhāgaśaḥ (according to the division of guṇa and activity);
guṇeṣu → guṇārthe (in the objects of the guṇas);
sajjate → majjate / saṁjate / sajyate (he sinks / he moves / he clings);

Śāṃkara

The key:
an excerpt from the commented verse
quotes from the scriptures
starting polemic

But as regards the wise man:		yaḥ punar vidvān —
But he who knows the truth, O mightyarmed, about the divisions of the energies and (their) functions, is not attached, thinking that the energies act upon the energies.		tattvavit tu mahābāho guṇa-karma-vibhāgayoḥ | guṇā guṇeṣu vartanta iti matvā na sajjate ||3.28||
He who is versed in the classification of the energies (guṇas) and their respective functions holds that the energies as sense-organs move amid the energies as sense objects, but not the Self. Thus holding, he forms no attachment (for actions).		tattvavit tu mahābāho | kasya tattvavit? guṇa-karma-vibhāgayoḥ guṇavibhāgasya karmavibhāgasya ca tattvavit ity arthaḥ | guṇāḥ karaṇātmakāḥ guṇeṣu viṣayātmakeṣu vartante na ātmā iti matvā na sajjate saktiṃ na karoti ||3.28||

Rāmānuja

prakṛter guṇaiḥ sattvādibhiḥ svānurūpaṃ kriyamāṇāni karmāṇi prati ahaṅkāravimūḍhātmā, ahaṃ karteti manyate; ahaṅkāreṇa vimūḍha ātmā yasyāsāv ahaṅkāravimūḍhātmā; ahaṅkāro nāma anahamarthe prakṛtāv ahamabhimānaḥ; tena ajñātasvarūpo guṇakarmasu ahaṃ karteti manyata ityarthaḥ / guṇakarmavibhāgayoḥ sattvādiguṇavibhāge tattatkarmavibhāge ca tattvavit, guṇās sattvādayaḥ guṇeṣu sveṣu kāryeṣu vartanta iti matvā guṇakarmasu ahaṃ karteti na sajjate

Śrīdhara

vidvāṃs tu na tathā manyate ity āha tattvavid iti | nāhaṃ guṇātmaka iti guṇebhya ātmano vibhāgaḥ | na me karmāṇīti karmabhyo ‚py ātmano vibhāgaḥ | tayor guṇa-karma-vibhāgayor yas tattvaṃ vetti sa tu na kartṛtvābhiniveśaṃ na karoti | tatra hetuḥ – guṇā iti | guṇā indriyāṇi guṇeṣu viṣayeṣu vartante nāham iti matvā

Madhusūdana

vidvāṃs tu tathā na manyata ity āha tattvavid iti | tattvaṃ yāthātmyaṃ vettīti tattvavit | tu-śabdena tasyājñād vaiśiṣṭyam āha | kasya tattvam ity ata āha guṇa-karma-vibhāgayoḥ | guṇā dehendriyāntaḥ-karaṇāny ahaṅkārāspadāni karmāṇi ca teṣāṃ vyāpāra-bhūtāni mama-kārāspadānīti guṇa-karmeti dvandvaikavad bhāvaḥ | vibhajyate sarveṣāṃ jaḍānāṃ vikāriṇāṃ bhāsakatvena pṛthag bhavatīti vibhāgaḥ sva-prakāśa-jñāna-rūpo ‚saṅga ātmā | guṇa-karma ca vibhāgaś ceti dvandvaḥ | tayor guṇa-karma-vibhāgayor bhāsya-bhāsakayor jaḍa-caitanyayor vikāri-nirvikārayos tattvaṃ yāthātmyaṃ yo vetti sa guṇāḥ karaṇātmakā guṇeṣu viṣayeṣu pravartante vikāritvān na tu nirvikāra ātmeti matvā na sajjate saktiṃ kartṛtvābhiniveśam atattvavid iva na karoti | he mahābāho ! iti sambodhayan sāmudrikokta-sat-puruṣa-lakṣaṇa-yogitvān na pṛthag-jana-sādhāraṇyena tvam avivekī bhavitum arhasīti sūcayati |

guṇa-vibhāgasya karma-vibhāgasya ca tattvavid iti vā | asmin pakṣe guṇa-karmaṇor ity etāvataiva nirvāhe vibhāga-padasya prayojanaṃ cintyam

Viśvanātha

guṇa-karmaṇor yau vibhāgau tayos tattvaṃ vettīti saḥ | tatra guṇa-vibhāgaḥ sattva-rajas-tamāṃsi | karma-vibhāgaḥ sattvādi-kārya-bhedā devatendriya-viṣayāḥ | tayos tattvaṃ svarūpaṃ | taj-jñas tu tattva-vit | guṇā devatāḥ prayojyānīndriyāṇi cakṣur-ādīni guṇeṣu rūpādiṣu viṣayeṣu vartante | ahaṃ tu na guṇaḥ, nāpi guṇa-kāryaḥ ko ‚pi, nāpi guṇeṣu guṇa-kāryeṣu teṣu me ko ‚pi sambandha iti matvā vidvāṃs tu na sajjate

Baladeva

vijñas tu na tathety āha tattva-vit tv iti | guṇa-vibhāgasya karma-vibhāgasya ca tattva-vit | guṇebhya indriyebhyaḥ karmabhyaś ca tat-kṛtebhyo yaḥ svayasa vibhāgo bhedas tasya tattvaṃ svarūpaṃ tat-tad-vaidharmya-paryālocanayā yo nāhaṃ guṇa-karma-vapuḥ iti vettīty arthaḥ | sa hi guṇā indriyāṇi guṇeṣu śabdādiṣu viṣayeṣu tat-tad-devatā-preritāni pravartante tān prakāśayanti | ahaṃ tv asaṅga-vijñānānandatvāt tad-bhinno, na teṣu tādrūpyeṇa varte, na tān prakāśayāmīti matvā teṣu na sajjante | kintv ātmany eva sajjate | atrāpi matvety anena kartṛtvaṃ jīvasyoktaṃ bodhyam