B.G 7.21-23
yo yo yāṁ yāṁ tanuṁ bhaktaḥ śraddhayārcitumicchati। tasya tasyācalāṁ śraddhāṁ tāmeva vidadhāmyaham ॥21॥
sa tayā śraddhayā yuktastasyārādhanamīhate। labhate ca tataḥ kāmān mayaiva vihitān hi tān ॥22॥
antavattu phalaṁ teṣāṁ tadbhavatyalpamedhasām। devān devayajo yānti madbhaktā yānti māmapi ॥23॥
Whosoever desires to worship with faith whichever form (deity), I (the Supreme Lord) make that very faith of his steady and unwavering.
Endowed with that faith, he strives for the worship of that (deity) and obtains his desires, which are indeed granted by Me only.
Worshippers of the other gods with limited intelligence go to those gods and reap fruits that are perishable. But My devotees come to Me and reap (imperishable fruit) as well.
Gīta Bhāshya 7.21-23
Testimonials from Narada and Brahma-Vaivarta Purāṇa are provided to further substantiate the efficacy of showing devotion to Lord Krishna compared to worship of other deities.
yāṁ yāṁ brahmādirūpāṁ tanum।
'Whichever, Whichever' - expression indicates various forms beginning with Lord Brahmā.
uktaṁ ca nāradīye -
It is stated in Nārada Purana:
"anto brahmādibhaktānāṁ madbhaktānām anantatā।"
"There is end (or boundary) for devotees of Brahmā and other lower deities, but there is no end to My (i.e. Lord Vishnu's) devotees."
-iti।
-stated thus.
"muktaśca kāṁ gatiṁ gacchet mokṣaścaiva kimātmakaḥ।"
"What destination would the one, liberated, attain? And, of what nature is liberation itself?"
ityādeḥ parihārasandarbhācca mokṣadharmeṣu।
While providing the resolution to such statements, in the 'mokṣadharm' section of Mahabharata, it is stated:
"avatāre mahāviṣṇoḥ bhaktaḥ kutra ca mucyate।"
"Among the incarnation of Lord Mahā Viṣṇu, the devotee gets liberated by worshiping any of the forms."
ityādeśca brahmavaivarte ॥21॥
- such are the directions from the Brahma-Vaivarta Purāṇa.
Gīta Tātparya 7.21-23
The distinction between the supreme lord Krishna and other deities and the distinction between the Lord and the other beings is brought out clearly in these verses.
...acetanayā tanmeyatvāttu māyayā। lakṣmyā vaśagayā loko viṣṇunaiva vimohitaḥ॥ ye tu viṣṇuṁ prapadyante te māyāṁ tāṁ taranti hi। lakṣmīḥ sā jaḍamāyā yā devatā te ubhe api॥
"... The insentient world is under the control of Lakṣmī, due to her association with Him (Lord Vishnu) and is certainly deluded by illusion, the Māyā. But those who surrender to Viṣṇu certainly cross over that Māyā. That Lakhmi is only both the insentient Māyā and the divinity Goddess.
viṣṇorvaśe tato'nanyabhaktyā taṁ śaraṇaṁ vrajet। yādr̥śī tatra bhaktiḥ syāt tādr̥śyanyatra naiva cet॥ ananyabhaktiḥ sā jñeyā viṣṇāveva tu sā bhavet। anyeṣu vaiṣṇavatvena lakṣmībrahmaharādiṣu॥
One should take refuge in Him with exclusive-devotion as everything is under His control. The kind of devotion that exists there (toward Viṣṇu) cannot exist elsewhere, certainly, never. "Exclusive-devotion" (ananya-bhakty) - should be understood as being directed only toward Viṣṇu. In others, such as Lakṣmī, Brahmā, Śiva, and others, it exists only in the context of their relationship with Viṣṇu (as Vaishnavas).
kuryāt bhaktiṁ nānyathā tu tadvaśā eva te yataḥ। evaṁ jānan tamāpnoti nānyathā tu kathañcana॥
One should not perform devotion to others, as they are indeed under His (Lord Vishnu's) control. Knowing this, one attains Him, not otherwise, not by any other means.
pūrṇaṁ vastu yato hyeko vāsudevo na cāparaḥ। evaṁviddurlabho loke yatsarve miśrayājinaḥ॥
The complete reality, the One, is the lord Vāsudeva alone, and there is no other. A knower of this truth is rare to find in the world, because most of them are seekers of mixed goals.
viṣṇuṁ tatparamajñātvā ramābrahmaharādikān। yajannapi tamo ghoraṁ nityuduḥkhaṁ prayāti hi॥
Worshipping Lakṣmī, Brahmā, Śiva, and other gods, one falls into terrible ignorance and attains constant suffering, failing to recognize Lord Viṣṇu as the Supreme.
ajñānāṁ tu kule jāto yāvadviṣṇoḥ samarcanam। viṣṇutattvaṁ ca jānīyāt tāvat sevā pr̥thak kr̥tā॥
One is born into the lineage of the ignorant, until they engage in proper worship of lord Viṣṇu. Till one understands the essence of Viṣṇu, any service performed remains incomplete.
vidyādyaihikabhogāya yadi buddhvā punarnatu। parivāratām r̥te kuryādanyadevārcanaṁ kvacit॥ ajānatā kr̥taṁ tyaktaṁ na doṣāya bhaviṣyati। janmādipradameva syādatyāge punareva tu॥ kṣipraṁ ca jñāpayatyeva bhagavān svayameva tu। yadi janmāntare svīyo nimittīkr̥tya kañcana॥"
ityādi ca।
But, if one engages in the austerities of other deities at anytime without knowledge, but abandons the same after knowing there is no defect. If understanding well (the supremacy of Lord Vishnu) one engages in wordly enjoyment, then indeed, it becomes the cause of further birth and consequences. The Lord indeed quickly reveals (the truth) in current or subsequent birth through Himself or by making one of His own (devotees) the cause.
- and such statements.
'matta eveti tān viddhi' ityupasaṁhārācca tattatkāraṇatvāt tattannāmetyavasīyate। 'mayi sarvamidaṁ protam' iti bhedenaiva upakramācca। āpnoti viṣṇumityeva ātma śabdo jñānini। 'yaccāpnoti yadādatte' ityādeḥ। 'āsthitaḥ sa hi', 'māṁ prapadyate' ityādi vākyaśeṣācca।
By concluding, 'Know them to be from Me alone' (7-12), it is determined that respective causes are responsible for respective identified names. The statement - 'All this is woven in Me' (7-7), indeed expresses distinction only (between the Lord and others) in the given context. The word 'ātma' in the context of 'attains Vishnu' indeed refers to the knower. There are such usages (in the Mahabharata) - 'That which attains and that which accepts', (referring to 'ātma'). (Distinction between supreme ātman and the being) is further clarified by expressions such as 'he who is established in Me,' and 'he surrenders to Me', etc.
[The quoted verse, referred by both Madhva and Shankara, is no longer part of BORI version of Mahabharata. The verse is 'यद् आप्नोति यद् आदत्ते यच् चाति विषयाणि च यच् चास्य सततो भावस् तस्माद् आत्मेति कीर्त्यते', which means 'That which attains, that which receives, that which transcends sense objects, and that which is its very nature — therefore, it is called the 'ātma'.]
bahūnāṁ janmanāmante jñānavān bhavati। tato māṁ prapadyate। vāsudevaḥ sarvamiti pūrṇamiti jānan। 'prapadyante'nyadevatāḥ' ityādi vākyaśeṣe bhedadarśanācca।
In 7-19 it is stated: "At the end of many births, one endowed with knowledge attains Me, surrendering with the understanding that Vāsudeva is all and complete". Later, in 7-20, it is stated 'those surrendering to other deities'. This clearly shows the distinction (between Lord Vāsudeva and other deities).
"devān devayajo yānti madbhaktā yānti māmapi"
"Those who worship the gods go to the gods, but My devotees come to Me". (7-23)
iti ca।
- stated thus as well.
"jñātvā paratvaṁ viṣṇostu pr̥thag devān yajannaraḥ। yāti devāṁn tadajñātvā tama eva prapadyate। tathāpi yāvadanyaistu sāmyaṁ hīnatvamekatām। na niścinvanti jāyante saṁsāre te punaḥ punaḥ॥"
“Even after knowing the supremacy of Vishnu, if a man worships the other gods as distinct, he goes to those gods, not knowing that he actually worships Me alone. Even so, as long as they do not determine inferiority of other gods and consider them to be equal to Me, they are born again and again in the cycle of worldly existence.”
iti ca ॥23॥
-stated thus as well (in ancient testimonial).