B.G 3.38, 39, and 40

धूमेनाव्रियते वह्निर्यथाऽदर्शो मलेन च। यथोल्बेनावृतो गर्भस्तथा तेनेदमावृतम् ॥३८॥

dhūmēnāvriyatē vahniryathā'darśō malēna ca। yathōlbēnāvr̥tō garbhastathā tēnēdamāvr̥tam ॥38॥

[धूमेन आव्रियते वह्निः यथा आदर्शो मलेन च। यथा उल्बेन आवृतो गर्भः तथा तेन इदम् आवृतम् ॥३८॥
dhūmēna = by smoke; āvriyatē = covered; vahniḥ = fire; yathā = just as; ādarśō = mirror; malēna = by dirt; ca = and;। yathā = just as; ulbēna = by the embryo; āvr̥tō = covered; garbhaḥ = womb; tathā = similarly; tēna = by that (desire); idam = this supreme being, the being, and the inner heart; āvr̥tam = is covered;॥]

Just as fire covered by smoke, mirror covered by dirt, and the womb covered by the embryo, is not seen, similarly, this (supreme being, the inner heart and the being) are covered by that (desire).

आवृतं ज्ञानमेतेन ज्ञानिनो नित्यवैरिणा। कामरूपेण कौन्तेय दुष्पूरेणानलेन च ॥३९॥

āvr̥taṁ jñānamētēna jñāninō nityavairiṇā। kāmarūpēṇa kauntēya duṣpūrēṇānalēna ca ॥39॥

[आवृतं ज्ञानम् एतेन ज्ञानिनो नित्यवैरिणा। कामरूपेण कौन्तेय दुष्पूरेण अनलेन च॥
āvr̥taṁ = covered; jñānam = knowledge; ētēna = by this; jñāninō = of the knower; nityavairiṇā = by the eternal enemy;। kāmarūpēṇa = in the form of desire; kauntēya = O son of Kunti (Arjuna); duṣpūrēṇa = difficult to satisfy; analēna= like fire, does not stay as is; ca = and;॥]

O son of Kunti, Arjuna, This knowledge of the knower is covered by the eternal enemy in the form of desire that is difficult to satisfy, and is like a fire that does not stay as is.

इंद्रियाणि मनो बुद्धिरस्याधिष्ठानमुच्यते। एतैर्विमोहयत्येष ज्ञानमावृत्य देहिनम् ॥४०॥

iṁdriyāṇi manō budidharasyādhiṣṭhānamucyatē। ētairvimōhayatyēṣa jñānamāvr̥tya dēhinam ॥40॥

[इंद्रियाणि मनो बुद्धिः अस्य अधिष्ठानम् उच्यते। एतैः विमोहयति एष ज्ञानम् आवृत्य देहिनम्॥
iṁdriyāṇi = the senses; manō = the mind; buddhiḥ = intellect; asya = its; adhiṣṭhānam = foundation; ucyatē = it is said;। ētaiḥ = by these; vimōhayati = bewilders; ēṣa = these; jñānam = knowledge; āvr̥tya = having enveloped; dēhinam = the embodied one;॥]

It is said that the senses, the mind, and the intellect are the places where it resides. By these desire envelops the knowledge of the embodied one.

Gīta Bhāshya 3.38, 39 and 40

'idam' i.e. 'this' is equated to the supreme being with the example of fire, to the inner heart by the example of mirror, and to the being with the example of embryo. 'tēna', i.e. 'that' is the desire which covers all three. 'kāmarūpēṇa' translates to 'known as desire'. 'duṣpūrēṇa', i.e. difficult to satisfy because desire always culminates in suffering. 'anala' i.e. 'fire' or 'one that does not stay as is'. Desire is the enemy to be defeated. So the place where it resides is revealed in the verse 3.40. 'Intellect is enveloped' means, orienting towards objects of senses.

कथं विरोधी सः। इदम् अनेनावृतम्। यथा धूमेन अग्निः आवृतः, प्रकाशरूपोऽपि अन्येषां न सम्यग्दर्शनाय तथा परमात्मा। यथा आदर्शः मलेनावृतः अन्यस्य अभिव्यक्तिहेतुः न भवति तथा अन्तःकरणं परमात्मादेः व्यक्तिहेतुः न भवति कामेन आवृतम्। यथा उल्बेन आवृत्य बद्धो भवति गर्भः तथा कामेन जीवः ॥३८॥

kathaṁ virōdhī saḥ। idam anēnāvr̥tam। yathā dhūmēna agniḥ āvr̥taḥ, prakāśarūpō'pi anyēṣāṁ na samyagdarśanāya tathā paramātmā। yathā ādarśaḥ malēnāvr̥taḥ anyasya abhivyaktihētuḥ na bhavati tathā antaḥkaraṇaṁ paramātmādēḥ vyaktihētuḥ na bhavati kāmēna āvr̥tam। yathā ulbēna āvr̥tya baddhō bhavati garbhaḥ tathā kāmēna jīvaḥ ॥38॥

[kathaṁ = how; virōdhī = opponent; saḥ = is that (desire);। idam = this being; anēnāvr̥tam = covered from that;। yathā = the way; dhūmēna = by smoke is; agniḥ = fire is; āvr̥taḥ = covered;, prakāśarūpō'pi = even though He is of the form of effulgence; anyēṣāṁ = for others; na = not; samyagdarśanāya = correctly perceived; tathā = simiarly; paramātmā = the supreme being;। yathā = the way; ādarśaḥ = mirror; malēnāvr̥taḥ = covered by dirt; anyasya = of another; abhivyaktihētuḥ = the cause of personality; na bhavati = does not become; tathā = similrly; antaḥkaraṇaṁ = the inner heart; paramātmādēḥ = of the supreme self; vyaktihētuḥ = the cause of personality; na bhavati = does not become; kāmēna āvr̥tam = covered by desire;। yathā = the way; ulbēna āvr̥tya = covered by embryo; baddhō bhavati = becomes bound; garbhaḥ = the womb; tathā = similarly; kāmēna = from desire; jīvaḥ = the being; ॥38॥]

How is the desire opponent? As this is covered by that, i.e. the way fire is covered by smoke, similarly even though the supreme being is of the form of effulgence, for others, He is not correctly perceived. The way a mirror covered by dirt cannot manifest the personality properly, similarly the inner heart covered by desire, cannot become the cause of one's personality. The way an embryo covered by womb becomes bound, similarly the being is bound by the desire.

शास्त्रतो जातमपि ज्ञानं परमात्मापरोक्ष्याय न प्रकाशते कामेन आवृतं ज्ञानिनोऽपि, किमु अल्पज्ञानिनः। कामरूपेण कामाख्येन नित्यवैरिणा। दुष्पूरेण दुःखेन हि कामः पूर्यते। न हि इन्द्रादिपदं सुखेन लभ्यते। यद्यपि इन्द्रादिपदं प्राप्तं पुनः ब्रह्मादिपदम् इच्छतीति लम्बुद्धिः न अस्तीति अनलः। उक्तं च-

śāstratō jātamapi jñānaṁ paramātmāparōkṣyāya na prakāśatē kāmēna āvr̥taṁ jñāninō'pi, kimu alpajñāninaḥ। kāmarūpēṇa kāmākhyēna nityavairiṇā। duṣpūrēṇa duḥkhēna hi kāmaḥ pūryatē। na hi indrādipadaṁ sukhēna labhyatē। yadyapi indrādipadaṁ prāptaṁ punaḥ brahmādipadam icchatīti lambuddhiḥ na astīti analaḥ। uktaṁ ca

[śāstratō = from scriptures; jātamapi = even though born; jñānaṁ = knowledge; paramātmāparōkṣyāya = direct perception of the Supreme being; na = not; prakāśatē = is manifested; kāmēna = desire; āvr̥taṁ = covered by; jñāninō'pi = even among the knowledgeable; kimu = what to speak of; alpajñāninaḥ = those with little knowledge;। kāmarūpēṇa = 'kāmarūpēṇa' means; kāmākhyēna = known as 'kāma' i.e. desire; nityavairiṇā = which is the eternal enemy;। duṣpūrēṇa = it is called 'duṣpūrēṇa', i.e. difficult to satisfy; duḥkhēna = by suffering; hi = indeed; kāmaḥ = desire; pūryatē = culminates;। na = not; hi =indeed; indrādipadaṁ = title of Indra and others; sukhēna = by pleasure/ easily; labhyatē = is attained;। yadyapi = even if; indrādipadaṁ = title of Indra and others; prāptaṁ = are obtained; punaḥ = again; brahmādipadam = the tile of Brahma and others; icchatīti = one desires; lambuddhiḥ = a deluded/ foolish; na astīti = does not stay as is; analaḥ = hence called 'anala', i.e. fire;। uktaṁ ca = Hence it is stated:]

Even though the knowledge is born from the scriptures, the direct perception of the Supreme being is not manifested, as knowledge is enveloped by desire even among the knowledgeable. 'kāmarūpēṇa' translates to 'known as desire', which is the eternal enemy. It is called 'duṣpūrēṇa', i.e. difficult to satisfy, as indeed, desire culminates in suffering. The title of Indra and others are not obtained easily. Even if the title of Indra and others are obtained, the deluded one again desires Brahma and such higher titles without being satisfied. Hence, it is called 'anala' i.e. 'fire' or 'one that does not stay as is'. Therefore, it is stated:

"ज्ञानस्य ब्रह्मणश्चाग्नेः धूमो बुद्धेर्मलं तथा। आदर्शस्याथ जीवस्य गर्भस्योल्बो हि कामकः॥"

"jñānasya brahmaṇaścāgnēḥ dhūmō buddhērmalaṁ tathā। ādarśasyātha jīvasya garbhasyōlbō hi kāmakaḥ॥"

[jñānasya = of knowledge; brahmaṇaścāgnēḥ = of Brahma, and, of fire; dhūmō = smoke; buddhērmalaṁ = impurity of understanding; tathā = similarly;। ādarśasyātha = of the mirror, like; jīvasya = of the living being; garbhasyōlbō = embryo to the womb; hi = indeed; kāmakaḥ = the cause of desire;]

"Like smoke is to fire, the knowledge is to Brahman, like dirt is to mirror, impurity is to intellect, and like womb to the embryo is desire to the living being."

इति ॥३९॥

iti ॥39॥

[iti = states testimonial;]

-states testimonials.

वधार्थं शत्रोः अधिष्ठानमाह - इंद्रियाणीति। एतैः ज्ञानम् आवृत्य। बुद्ध्यादिभिर्हि विषयगैः ज्ञानम् आवृतं भवति ॥४०॥

vadhārthaṁ śatrōḥ adhiṣṭhānamāha - iṁdriyāṇīti। ētaiḥ jñānam āvr̥tya। buddhyādibhirhi viṣayagaiḥ jñānam āvr̥taṁ bhavati ॥40॥

[vadhārthaṁ = for the sake of slaying; śatrōḥ = of the enemy; adhiṣṭhānamāha = stated as the foundation; iṁdriyāṇīti = through 'iṁdriyāṇi', i.e. senses verse;। ētaiḥ = by these; jñānam = the knowledge; āvr̥tya = having covered;। buddhyādibhirhi = 'indeed, by the intellect and others'; viṣayagaiḥ = 'with the object of senses' jñānam = knowledge; āvr̥taṁ bhavati = gets enveloped; ॥40॥]

To make it easy to kill the enemy (in the form of desire), its foundation is explained in the verse 'iṁdriyāṇi', i.e. senses. These envelopes the knowledge, means the intellect becomes covered by knowledge related to the objects of senses.