A statement from the vaikhAnasa kalpa–sutra to the effect that all Vedic rites,
austerities and sacrifices prescribed in the Vedas are only variant form of worship of Vishnu,
” athatOnushtAnakalpam vyaKhyAsyAma: | sarvE vaidikAchArAstapOyagnaSva vishNupUjAvidhErbhEdA: | iti vaikhAnasa sUtram || ”
The ancient lawgivers knew that in the worship of vishnu the vaikhAnasas were only following the lead given by the great sages of yore like vasishTa, the ascetics like sanaka, and by the section of the ancient followers of the Vedic tradition who were the adherents of the cult vishnu.

Although the vaikhAnasa texts align themselves  against the tAntrik tradition, there is at least one particular detail of worship which they share in common with the latter, and that is the assumed identification of the devotee with the deity during worship. The tAntrik position rejects as impossible the communion of the human with the divine, unless the worshipper identifies himself with the worshipped. The worshipper is said to pass through three phases: he regards himself as wholly belonging to the deity, without however a direct encounter with the deity (‘tasyaivAham‘); then, an encounter does occur and the devotee can confide with the deity: ‘I am thine’ (‘tavevAham‘); and finally the culmination of the encounter results in the feeling that the worshipper himself is the deity. And thus the deity does not exist apart from him (‘tvamevAham‘). In the vaikhAnasa texts, it is prescribed for purposes of invocation (AvAhana) that after the worship of the enclosure-deities (Avarana-pujA ) and the worship of the door-guardians ( dvAra-pAla-puja ), the priest should station himself in front of the idol (behind the screen), and reciting the ‘Atma-suktaM‘, should enter into a state of meditative absorption, when he will become in fact vishnu himself. Then follows the sequence of symbolic and ritual ‘placement’ (nyAsa), after this identity of self with Vishnu is transferred to the main idol. Derived from this facility with which the priest can identify himself with the Deity during a worship sequence is the notion that the priest has an enduring divine presence within him. We read, for instance, in BhrigU’s KriyAdhikAra that Vishnu has two forms: the Idol and the Priest. The idol acquires divinity after invocation (AvAhana), while divinity abides always in the priest. He is therefore to be regarded as a mobile god viz., sAkshAt vishnu rupi.

“rUpadvayam hareH prOkta bimbamarchaka Eva cha | bimbam tvAvAhanAdUrdhvam sadA sannihitOarchaka || archakastu hariH sAkshAtchhara rUpi na samsayaH |

The Atma-Sukta (SrI vaikhAnasa Mantra Prasna, 5.120.1-12 ) is a collection of nine verses in the trishtubh metre. Its employment is peculiar to the vaikhAnasa worship. It is recited while invoking the form of Vishnu in his cosmic aspect (sa-kala), and it is meant to enlarge the consciousness of the worshipper to cosmic dimensions so that his own constitution may accommodate Vishnu’s ‘sakala‘ form. It is a procedure by means of which the priest’s self identifies itself with the highest of selves, viz., bishnu. The hymn is called Atma-Sukta not only because it begins with the words ‘AtmAtma‘, but also because it concerns itself with transforming the individual self into the cosmic spirit. ( We may call it advaitic element in qualified non dualism )

[ Note :-(ग्)ं is sign for vedic anusvAra . ]
५.१.१२०. १
आत्मात्मा परमान्तरात्मा मह्य्-अन्तरात्मा यश् चातिरात्मा सतनो | ऽन्तरात्मा व्यावेष्टि विश् (ग्)ं सकलं बिभर्ति यो व्यक्त-पुण्यस् स-तुनः प्रधानः||

५.१.१२०.२ प्राणः प्रणीतिस् स उदान आदिर् वर-दो वराहो व्यानश् च मे स्यात् | तपसाञ् च मूर्तिः कपिलो मुनीन्द्रो यश् चापानो हयशीर्षो नः||

५.१.१२०.३ यत् सर्वम् अश्नात्य् अजरस् समग्र(ग्)ं श्रियम् ऊर्ज-युक्तां स तु मे समानः||

५.१.१२०.४ बलम् आसुरं यत् सततं निहन्ता ब्रह्मा बुद्धिर् मे गोप ईश्वरः||

५.१.१२०.५ सविता च वीर्यम् इन्दुश् च धातु-रस-भूत-भूता भूतास् स-भूताः||

५.१.१२०.६ द्यौर् मे अस्तु मूर्धोदर-नाभो वा भूमिर् यथाङ्घ्रिर्ववृधे ऽहम् ईशः||

५.१.१२०.७ अस्थीनि मे स्युर् अथ पर्वताख्या भुजगाश् च केशा दिवि ये चरन्तः||

५.१.१२०.८ द्वौ नेत्र-रूपौ विथु पृश्च्नि [?] मुख्यौ रुधिरञ् च सार(ग्)ं सकलञ् च तोयम् ||

५.१.१२०.९ स्नायवो मे आसन्ना द्यौर् भृगुर् मे हृदयम् अस्तु | सर्वे अन्ये मुनयो ऽङ्ग-भूता वेदा मे आस्यं जिह्वा मे सरस्वती ||

५.१.१२०.१० दन्ता मरुत उपजिह्वा उपश्रुतिः ||

५.१.१२०.११ वृषणौ मित्रा-वरुणाव् उपस्थः प्रजा-पतिर् आन्त्रा मे वेदाश् श्रुति-स्मृती मेदाधारणे ||

५.१.१२०.१२ स्वेदम् मे वर्षं मूत्र कोश(ग्)ं समुद्रं पुरीषं काञ्चनम् ||

५.१.१२०.१३ सावित्री गायत्री मर्यादा वेदि-हृत्-पुण्डरीके विमले प्रविष्टस् | सकलस् स-लक्ष्मीस् स-विभूतिकाङ्गो यत् सर्वं पुण्यं मय्य् अधिष्ठानम् अस्तु ||

५.१.१२०.१४ सर्वेषां देवानाम् आत्मकस् सर्वेषां | मुनीनाम् आत्मकस् तपो-मूर्तिर् इह पुण्य-मूर्तिर् आसन् ||

Translation:-

That which is the self of the self, the supreme self, the inner self, the inner self of the earth, and the primordial self, is indeed our inmost self; It pervades the universe and sustains all things. As if the merit manifests itself, it is our chief.
The outward breath (prAna) is our guide (praniti); the upward breath (udAna) is the primordial and boon-bestowing boar (varAha); the spreading breath (vyAna) is the form of Kapila, the sage who is the personification of penance; the downward breath (apAna) is the horse-headed deity, Hayagriva. 

My digestive breath (samAna) is that which devours everything, even goddess of prosperity (Sri) with her energy; my strength vanquished at all times evil forces, and my intellect is verily Brahma, and Isvara is my protector.
Savitri (the aspect of Sun-god) is my sex energy, the moon is the watery ingredients in my body; the five basic elements (bhutas: earth, water, fire, air and akasa) are the constituents of my body; the sky is my head, the mid-region is my belly; and the spreading earth constitutes my feet; I am indeed the ruler of all things.
My bones should verily be called the mountains; my hairs are the serpents that move about in the heavens; my two eyes are the wide earth and the high sky; and my blood is the essential watery content of the universe.
My sinews are the rivers on the earth, my heart is Bhrigu himself (the Vaikhanasa Sage) and my limbs are all the other sages; my mouth represents the Vedic lore and my tongue is the goddess of speech, Sarasvati; the windgods (maruts) are my teeth, and my epiglottis is the revelation of the sacred texts.

My testicles are the twin gods, Mitra and Varuna, my sex organ is the creator, Prajapati; my entrails are the Vedic hymns; my intellect (medha) and retention (dharana) are the revealed texts (sruti) and the texts subsidiary to them (smriti); my perspiration is indeed the rains, and my bladder is the ocean itself; my fecal matter is gold.
The hymn in the gayatri metre addressed to the sun-god (Savitri) is the sacred precincts and the altar; and into the pure lotus of my heart has entered Vishnu in His cosmic aspect (sakala), along with the goddess of wealth (srI), in all His glory; may all that is filled with merit in me provide for Him a foothold.
May I contain in myself the essence of all the gods and all the sages, may I be a personification of austerities (tapo-murti) and of all merit (punya-murti)”. The purpose of the ritual of invocation (AvAhana) of the supreme, transcendental and all-pervading Vishnu (the etymological meaning of the word Vishnu is ‘pervader’) in the heart of the devotee or in an idol is to facilitate contemplation of the deity in one place; even as the fire which spreads all over the forest blazes forth especially in some places. Invoked by appropriate mantras in the idol, or meditated intensely and devotedly in the heart, Vishnu makes his presence felt in the idol or in the heart, and receives the worship offered (Kriyadhikaram).

Vaikhanasa worship is essentially Vishnu-oriented, but Vishnu is worshipped in his comprehensive and pervasive aspect (in accordance with the root meaning of the word ‘vishi vyApatau’); and when Vishnu is invoked for worship, his presence includes the presence of all the other gods as his retinue (saparivara). Hence worship of Vishnu means worship of all the gods
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