Recently, somebody asked on Quora
Do most Hindus, unlike followers of ISKCON, believe Vishnu is the supreme source, not Krishna?
An ISKCON devotee expressed the view that this is indeed true. Then Rami Sivan, a sometimes controversial Śrī Vaiṣṇava with Western roots, gave a detailed refutation of this view:
A good question which is often asked. Only ISKCON considers Krishna as the source of incarnations.
Most Vaisnavas and other Hindus don’t make any quantitative theological differences between Vishnu and His avataras.
The Vedas are the Supreme Authority – Krishna is not mentioned by name in any of the Veda Samhitas but in the Chandogya Upanishad he is mentioned once. Vishnu on the other hand is mentioned several times in the Veda Samhitas.
Now a parsing of Sanskrit terms is the key to understanding theology. There are three names which are considered as truly indicative of the Supreme Being — and they are considered as supreme because all three are indicative of All-pervasiveness – i.e. omnipresence of the Divine.
- nārāyana — which means the ground of all Being – the source of all manifestation of both the material universe and the individual selves.
- viṣṇu — which means that which pervades everything from within.
- vāsudeva — that which pervades everything from without.
I will now give you a sample of testimonies from the various Scriptures. There are hundreds of such testimonies.
nārāyaṇaḥ paraṃ brahma tattvaṃ nārāyaṇaḥ paraḥ |
nārāyaṇaḥ paro jyotir ātmā nārāyaṇaḥ paraḥ ||
Nārāyaṇa is the Supreme Reality designated as Brahman. Nārāyaṇa is the Highest. Nārāyaṇa is the Supreme Light (described in the Upaniṣads). Nārāyaṇa is the Highest. (Mahānārāyaṇa Upaniṣad Anuvāka 13 Verse 4.)
eko nārāyaṇo devo devānāmīśvareśvaraḥ |
paramātmā paraṃ brahma janmādyasya yato bhavet ||
The lord Nārāyaṇa alone is the omnipotent almighty of all the gods. He is the Supreme Being. He is the Supreme Brahman. All this world originates from Him. (Garuda Purāṇa ch 1 vs 12 )
viṣṇor aṃśaṃ bhuvaṃ yāte ṛtavasca abhavat śubham |
When the portion of Vishnu became manifest upon the earth (as Krsna) the seasons became congenial. (VP. 5:2:4.)
yadośca dharma śīlasya nitarāṃ muni sattama |
tatrāṃśena avatīrṇasya viṣṇo vīryāṇi śaṃsanaḥ ||
You have also described the line of the noble and righteous king Yadu. In that dynasty Mahavishnu was incarnated by a part of His splendour. (SBh. 10:1:2)
saptamo vaiṣṇavam dhāma yam anantaṃ pracakṣate |
garbho babhūva devakyā harṣa śoka vivardhanaḥ ||
She bore that manifestation of Vishnu called Ananta in her seventh pregnancy, which was the cause of delight and fear to her at the same time. (SBh 10:2:5)
devakyāṃ deva rūpiṇyāṃ viṣṇuḥ sarva guhāśayaḥ |
āvir āsīd yathā prācyāṃ diśi indur iva puṣkalaḥ ||
Vishnu the resident in the hearts of all, was born of the divinely beautiful Devaki, like the full moon rising on the eastern horizon. (Suka) (SBh 10:3:8)
Then finally from the GOSWAMIS
“The omniscient great God of Vaikunta (viz. Sriman Narayaṇa) at once manifested Himself before me as Sri Krishna, the eternal son of Nanda and forthwith Sri Lakshmi Devi became Radhika followed by Bhudevi as Candravalli.”
Stated by Srila Sanatana Goswami in Sri Brhat Bhagavatamṛtam Part 2 Chap 4 (Vaikuṇtha nama) published by Gaudiya Maṭha
I hope this clarifies for you the orthodox position.