Vaishnavism
Vedic scriptures usually quoted by Vaishnavas to point to Narayana as the Supreme Being, Bhagavan (Parabrahman in advaita terminology):
nityo nityanam chetanas chetananam eko bahunam yo vidadhati kaman
He is the prime eternal among all eternals. He is the supreme living entity of all living entities, and He alone is maintaining all life. (Katha Upanishad 2.2.13)
ete camsa-kalah pumsah krishnas tu bhagavan svayam indras vyakulam lokam mrdayanti yuge yuge
All incarnations are either plenary portions or expansions of plenary portions appearing in various universes to protect the theists; but Lord Krishna is the original supreme lord and the source of all. (Bhagavata Purana 1.3.27-28)
isvara paramah krishna sac-cid-ananda vigrahah anadir adir govindah sarva karana karanam
Lord Krishna is the supreme absolute controller, whose form comprises immortality, omniscience, and bliss. He is without beginning, the origin of all, the cause of all causes and the source of the Vedas. (Brahma Samhita 5.1)
namo brahmanya-devaya go-brahmana-hitaya ca jagad dhitaya krsnaya govindaya namo namah
Let me offer my humble obeisance unto Lord Vishnu, who is the worshipable deity for all brahminical people, who is the well-wisher of the cows and brahmanas and who is always benedicting all the universes. (Vishnu Purana 1.19.65)
Krishna Himself confirms this in the Bhagavad-Gita:
mattah parataram nanyat kincid asti dhananjaya mayi sarvam idam protam sutre mani-gana iva
There is no truth superior to Me. Everything rests upon Me, as pearls are strung on a thread. (Bhagavad Gita 7.7)
arjuna uvaca, param brahma param dhama pavitram paramam bhavan purusham sasvatam divyam adi-devam ajam vibhum
Arjuna said: You are the Supreme Brahman, the ultimate abode, the purest, the Absolute Truth. You are the eternal, transcendental, original Person, the unborn, the greatest. (Bhagavad Gita 10.12)
bhajagovindam bhajagovindam govindam bhajamuudhamate naamasmaranaadanyamupaayam nahi pashyaamo bhavatarane
Worship Govinda, worship Govinda, worship Govinda, Oh fool! Other than chanting the Lord's names, there is no other way to cross the life's ocean. (Bhaja Govindam, composed by Adi Shankaracharya)
naaraayana paro jyotir-aatmaa naarayana para, naarayanam param brahma tatvam naarayanam para, naarayana paro dhyaata dhyaanam naaraayana para
Narayana is, Para Jyoti, the greatest light, Para Atma, the super soul (Paramatman), Para Tatvam, the best of essences, Para Dhyata, the greatest meditator, Para Dhyanam, the best of meditations. (Narayana Sukta verse 4)
In Vaishnavism, ParaBrahman is the source of the Brahman effulgence and Vishnu or Krishna is established as the Supreme Personality of Godhead.
yasya prabha prabhavato jagad-anda-koti-kotishv asesha-vasudhadi vibhuti-bhinnam tad brahma nishkalam anantam asesha-bhutamgovindam adi-purusham tam aham bhajami
Govinda, is the primeval Lord, whose effulgence is the source of the nondifferentiated Brahman mentioned in the Upanishads, being differentiated from the infinity of glories of the mundane universe appears as the indivisible, infinite, limitless, truth. (Brahma Samhita 5.40)
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