MI.U 1.01

एष पन्था एतत् कर्म एतद् ब्रह्मैतत् सत्यम्। तस्मान्न प्रमाद्येत् तम् नातीयात् ज न ह्यत्यायन् पूर्वे। येऽत्यायन् ते पराबभूवुः॥

This is the path, this is the action, this is Brahman, this is truth. Therefore, one should not be negligent, nor should one overstep it; for those who overstepped before, they perished.

तदुक्तमृषिणा -

That which was spoken by the sage -

प्रजा ह तिस्रो अत्यायमीयुर्न्या अर्कमभितो विविश्रे। बृहद्ध तस्थौ भुवनेष्वन्तः पवमानो हरित आविवेशेति।

Indeed, three offspring have moved downwards, other three have transcended and entered towards the Lord Arka from all sides. The great one stood within the worlds; the purifying Pavamāna, the one who carries, has thus entered.

प्रजा ह तिस्रो अत्यायमीयुरन्ति या वै ता इमाः प्रजास्तिस्रो अत्यायमायंस्तानीमानि वयांसि वङ्गा वगधाश्चेरपादाः।

Indeed, three groups of offspring have migrated beyond; beyond the three offspring — namely, these tribes: the Vangas (the curved ones), the Vagadhas (sensually and materially driven), and the Cerapadas (violent, lawless).

न्यन्या अर्कमभितो विविश्र इति ता इमाः प्रजा अर्कमभितो निविष्टा इममेवाग्निम्।

Thus, by another path, those creatures entered around Lord Arka; these creatures are settled around Lord Arka, which is indeed this Agni.

बृहद्ध तस्थौ भुवनेष्वन्तरिति आद उ एव बृहद् भुवनेष्वन्तरसावादित्यः। पवमानो हरन्ति आविविशेति वायुरेव पवमानो दिशो हरन्ति आविष्टः॥१॥

Thus, the great one stood within the worlds; at the beginning, indeed, only the great one within the worlds, that is the Lord Aditya. The purifying one, Pavamāna carries (things), having entered; the wind itself is the purifying one, the directions carry (things), having entered.

MI.Bāshya 1.01

A testimonial from Rig Saṁhitā is quoted, providing the context in which the Aitareyī Upanishad teachings were revealed to Bahvṛca seer. This knowledge came directly from Lord Vishnu to Goddess Lakshmi, from her to Lord Brahma, and then to the rest of the gods.
The stated path here refers to the path that takes one directly to the Supreme Lord, who is eternally the source of action, the mother, the agent, being full of qualities, the truth, and the cause of one's own attainment. One should never forget Him anywhere - is the path.
The three types of beings who are after righteousness, knowledge, and dispassion, transcend and reach Lord Vishnu within the Sun, who is also called 'Arka' and 'Aditya'. They are purified by Pavamāna, the Lord Vishnu within the wind god, through renunciation of action and self-study. Those who are after wealth and sovereignty are lower beings bound to earth. 'Vayāṃsi' - those who abandon things or meat eaters, also known as 'Piśācas'; 'Vangas' - that which is curved or bent, i.e. crucked minded; 'Vagadhāḥ' - sensually driven, materially attached; 'Cerapādāḥ' - Violent, lawless, and disruptive.

"प्रादुर्बर्भूव भगवांस्तपसेतराया नारायणोऽब्जजसुतस्य विशालाम्नः। तस्मिन् गतेऽध्वरमभूत सुरविप्रसङ्घो निश्चेतनस्तदनु पद्मभवोऽमुमस्तौत्॥

"The Lord Nārāyaṇa, distinct from the ascetic, became manifest for the son of the lotus-born, of Viśālāmnā. When he departed from the sacrifice, the assembly of gods and sages became unconscious. Then, the lotus-born (Brahmā) praised him.

तेन स्तुतः स भगवान् गिरिशेन्द्रमुख्यान् सर्वानबोधयदजेन सहैव तेऽथ। दासत्वमापुरत एव महत्सुराणां दासत्वतः स महिदास इति प्रसिद्धः॥

Having been praised by him, the Lord made all the foremost among the lords of mountains aware, together with Aja (Brahmā). Then, they indeed attained servitude to the great gods; from this servitude, he became well-known as Mahidāsa.

शृण्वत्सु तेषु भगवान् वदद् रमायै दिव्यां श्रुतिं स परमोऽतिमुदैतरेयीम्। सा बह्वृचैः प्रपठिता चतुराननास्याद् यस्यां रहस्यमुदितं परमं हि विष्णोः॥

While they were listening, the Lord, addressing Ramā, joyfully spoke the divine Aitareyī revelation. That revelation, recited by the Bahvṛca seers, originated from the mouth of the four-faced Brahmā, in which the supreme secret of Viṣṇu is indeed revealed.

महाभूतिः श्रुतिः सैषा महाभूतिर्यतो हरिः। विशेषेणात्र कथितः सर्वज्ञः शाश्वतः प्रभुः॥"

This revelation is the great manifestation from whom Hari (the Lord) arises. Here, specifically, the omniscient, eternal Lord is described."

इति ऋक् संहितायाम्।

- stated thus, in the Ṛg Saṁhitā.

एष एव सदा "पन्था" भगवान् पुरुषोत्तमः। नित्यं स्वप्राप्तिहेतुत्वात् कर्तृत्वात् कर्म मातृतः॥ ब्रह्मैष गुणपूर्णत्वात् सत्यं साधुस्वरूपतः। क्वापि तं विस्मरेन्नैव त्यक्त्वा तं नेतरं व्रजेत्॥ पूर्वे नैनं तत्यजुर्हि ब्रह्माद्यास्तेन संसृतेः। मुक्ताः श्रीश्च तदत्यागान्नित्यमुक्ता गुणाधिकाः॥

This indeed is always the very "path" — the Lord, the Supreme Person. Because He is eternally the cause of one's own attainment, the agent, the source of action, and the mother; this Brahman, being full of qualities, is truth and of virtuous nature. One should never forget Him anywhere, nor, having abandoned Him, go to another. The former ones, Brahma and others, indeed did not abandon Him, and by Him were liberated from transmigration. The liberated ones and Lakshmi, by never abandoning Him, are eternally liberated and superior in qualities.

विहायस्ययनात् प्रोक्ता वयांसीति पिशाचकाः। वर्तितज्ञानतो वङ्गा नरास्तैरवनं सदा॥

From the act of leaving and going, they are called 'vayāṃsi', the Piśācas; from the knowledge of conduct, the Vaṅgas, men by them always (inhabit) the earth.

अन्नरूपैर्गृध्नवो हि वङ्गावगध नामकाः। राक्षसा असुरा ईरपादा इति समीरिताः॥

Those greedy ones, taking such forms of food, are known as Vanga and Avagadha, and are called rākṣasas, asuras, and Cherapādas.

धर्मो ज्ञानं च वैराग्यं ऐश्वर्यं चतुरात्मकः। वायुर्देवोऽत्रासुराणां ऐश्वर्यं गुण एव हि॥

Righteousness, knowledge, dispassion, and sovereignty are of a fourfold nature, and Vāyu is the deity here. Sovereignty and wealth alone are truly the qualities of deamons.

ईरपादास्ततः प्रोक्तास्ते त्रयो विष्णुमत्यजन्। पराभूतास्ततस्ते तु तमस्यन्धे निपातिताः॥

Those swift-footed ones, thus spoken of, those three did not reach the mind established in Lord Vishnu. Defeated, therefore, they were cast down into utter darkness.

देवाश्च ऋषयो मर्त्यसत्तमा इति च त्रयः। आश्रिता विष्णुमेवैकं त्रिस्थानस्थितमच्युतम्॥

The gods, the seers, and the best among mortals — these three have all taken refuge in Lord Viṣṇu alone, the one infallible being who abides in the three worlds.

अग्निस्थमाश्रिता मर्त्या विष्णु मर्का भिधं परम्। आ जनैरर्चितत्वात् स ह्यर्क इत्युच्यते हरिः॥

Hari, who is Lord Viṣṇu, is situated in fire and is resorted to by mortals; because he is worshipped by people as the supreme, he is called Arka, the Sun.

अग्नौ कर्माणि कृत्वैव मानुषा मुक्तिभागिनः। कर्मभिः शुद्धसत्त्वानां कर्मत्यागोऽपि नान्यथा॥

Humans who perform actions in the fire indeed become eligible for liberation; for those whose essence is pure, renunciation of action is also only through actions, not otherwise.

आश्रिताः सूर्यगं विष्णुमृषयो बृहदित्यसौ। तेजसा बृंहणादुक्तो विष्णुरादित्य इत्यपि॥

The sages who go to the sun have resorted to Lord Viṣṇu and call him 'great'; thus, because of his brilliance and his power to increase, Viṣṇu is also called Āditya.

आदानात् सर्ववस्तूनां स्वाध्यायेनामुमाश्रिताः। मुच्यन्त ऋषयो नित्यं नान्यथा तु कथञ्चन॥

By abstaining from taking all objects and resorting to self-study, sages are always liberated; never otherwise, in any way.

वायुस्थमाश्रिता देवाः पवमानाभिधं हरिम्। संसारात् पावयित्वा यत् महानन्दे मिनोत्ययम्॥

The gods, having taken refuge in Hari called Pavamāna, who is established in air, after being purified from saṃsāra, attain this one who measures (or grants) great bliss.

पवमानस्ततो विष्णुर्व्याप्तः सर्वासु दिक्षु च। आश्रितो भगवान् सर्वैः सर्वत्रापि विशेषतः॥ आश्रयात् पृथगुक्तोऽयं नित्यानन्दो रमापतिः॥

Thus, the purifying Lord Viṣṇu pervades all directions and is resorted to by all everywhere, especially; apart from the refuge, this Lord of Lakṣmī, who is eternal bliss, is said to be distinct.