BhG 3.6

syntax

yaḥ (he who) karmendriyāṇi (the senses of activities) saṁyamya (after restraining)
manasā (by the mind) indriyārthān (objects of the senses) smaran (remembering) āste (he remains),
saḥ (he) vimūḍhātmā (whose self is bewildered) mithyācāraḥ (a hypocrite) ucyate (he is called).

grammar

karmendriyāṇi	–	karma-indriya 2n.3 n.; TP: karmaṇām indriyāni iti – senses of activities (from: √kṛ – to do, karman – activity and its result; √ind – to be powerful, indriya – the senses; vāk-pāṇi-pāda-pāyūpastha-saṁjñakāni – they are named: organ of speech, hand, foot, anus, genital);
saṁyamya	–	sam-√yam (to restrain) absol. – after restraining;
yaḥ	–	yat sn. 1n.1 m. – he who;
āste	–	√ās (to sit, to exist) Praes Ā 1v.1 – he sits, he remains;
manasā	–	manas 3n.1 n. – by the mind (from: √man – to think);
smaran	–	smarant (√smṛ – to think, to remember) PPr 1n.1 m. – [while] remembering;
indriyārthān	–	indriya-artha 2n.3 m.; TP: indriyāṇām arthān iti – objects of the senses (from: √ind – to be powerful, indriya – the senses; √arth – to strive to obtain, to desire, to request, artha – purpose, advantage, concern, object, wealth);
vimūḍhātmā	–	vi-mūḍha-ātman 1n.1 m.; BV: yasyātmā vimūḍho ‘sti saḥ – whose self is bewildered (from: vi-√muh – to become confused, bewildered, stupefied, PP vimūḍha – bewildered; ātman – self);
mithyācāraḥ	–	mithyā-ācāra 1n.1 m.; yo mithyācārati saḥ – who behaves falsely, hypocrite (from: av. mithyā – incorrectly, falsely, deceitfully; ā-√car – to come near to; ācāra – custom, good conduct);
saḥ	–	tat sn. 1n.1 m. – he;
ucyate	–	√vac (to speak) Praes. pass. 1v.1 – he is called;

textual variants

ya āste → āste ca / tathāste (and he remains / thus he remains);
mithyācāraḥ → mūḍhācāraḥ (whose conduct is bewildered);

Śāṃkara

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

The unenlightened should not give up Karma-Yoga. Now, for him who knows not the Self, it is not right to neglect the duty enjoined on him. So, the Lord says:		yat tv anātmajñaḥ coditaṃ karma nārabhate iti tad asad evety āha –
He who, restraining the organs of action, sits thinking in his mind of the objects of the senses, self-deluded, he is said to be one of false conduct.		karmendriyāṇi saṃyamya ya āste manasā smaran | indriyārthān vimūḍhātmā mithyācāraḥ sa ucyate ||3.6||
The organs of action are the hand, &c. The self-deluded man, the man whose antah-karaṇa is thus deluded, is called a hypocrite, a man of sinful conduct.		karmendriyāṇi hastādīni saṃyamya saṃhṛtya ya āste tiṣṭhati manasā smaran cintayan indriyārthān viṣayān vimūḍhātmā vimūḍhāntaḥ-karaṇo mithyācāro mṛṣācāraḥ pāpācāraḥ sa ucyate ||3.6||

Rāmānuja

anyathā jñānayogāya pravṛtto mithyācāro bhavatīty āha

avinaṣṭapāpatayā ajitāntaḥkaraṇaḥ ātmajñānāya pravṛtto viṣayapravaṇatayā ātmani vimukhīkṛtamanāḥ viṣayān eva smaran ya āste, anyathā saṃkalpya anyathā caratīti sa mithyācāra ucyate / ātmajñānāyodyukto viparīto vinaṣṭo bhavatītyarthaḥ

Śrīdhara

ato ‚jñaṃ karma-tyāginaṃ nindati karmendriyāṇīti | vāk-pāṇy-ādīni karmendriyāṇi | saṃyamya bhagavad-dhyāna-cchalena indriyārthān viṣayān smarann āste aviśuddhatayā manasā ātmani sthairyābhāvāt, sa mithyācāraḥ kapaṭācāro dāmbhika ucyata ity arthaḥ

Madhusūdana

yathā-kathaṃcid autsukya-mātreṇa kṛta-saṃnyāsas tv aśuddha-cittas tat-phala-bhāṅ na bhavati yataḥ | yo vimūḍhātmā rāga-dveṣādi-dūṣitāntaḥ-karaṇa autsukya-mātreṇa karmendriyāṇi vāk-pāṇy-ādīni saṃyamya nigṛhya bahir-indriyaiḥ karmāṇy akurvann iti yāvat | manasā rāgādi-preritendriyārthān śabdādīn na tv ātma-tattvaṃ smarann āste kṛta-saṃnyāso ‚ham ity abhimānena karma-śūnyas tiṣṭhati sa mithyācāraḥ sattva-śuddhy-abhāvena phalāyogyatvāt pāpācāra ucyate |

tvaṃ-padārtha-vivekāya saṃnyāsaḥ sarva-karmaṇām |
śrutyeha vihito yasmāt tat-tyāgī patito bhavet ||

ity ādi-dharma-śāstreṇa | ata upapannaṃ na ca saṃnyasanād evāśuddhāntaḥ-karaṇaḥ siddhiṃ samadhigacchatīti

Viśvanātha

nanu tādṛśo ‚pi sannyāsī kaścit | kaścid indriya-vyāpāra-śūnyo mudritākṣo dṛśyate ? tatrāha karmendriyāṇi, vāk-pāṇy-ādīni nigṛhya yo manasā dhyāna-cchalena viṣayān smarann āste, sa mithyācāro dāmbhikaḥ

Baladeva

nanu rāga-divyāpāra-śūnyo mudrita-śrotrādiḥ kaścit kaścid yadi dṛśyate tatrāha karmendriyāṇīti | yo yatiḥ karmendriyāṇi vāg-ādīni saṃyamya manasā dhyāna-chadmanā indriyārthān śabda-sparśādīn smarann āste sa vimūḍhātmā mūrkho mithyācāraḥ kathyate | sa ca niruddha-rāgāder ajñasya niṣkāma-karmānuṣṭhānena manaḥ-śuddher anudayāt śrotrādy-aprasāre ‚py aśuddhatvān manasā tad-viṣayāṇāṃ sma raṇāj jñānāyodyatasyāpi tasya jñāna-lābhāt mithyācāro vyartha-vāg-ādi-niyama-kriyo dāmbhika ity arthaḥ