In the Upaniṣads it is stated, yad-bhīṣā vātaḥ pavate: "It is out of the fear of the Supreme Lord that the wind is blowing." (Taittirīya Upaniṣad 2.8.1) In the Bṛhad-āraṇyaka Upaniṣad (3.8.9) it is stated, etasya vā akṣarasya praśāsane gārgi sūrya-candramasau vidhṛtau tiṣṭhata etasya vā akṣarasya praśāsane gārgi dyāv-āpṛthivyau vidhṛtau tiṣṭhataḥ. "By the supreme order, under the superintendence of the Supreme Personality of Godhead, the moon, the sun, and the other great planets are moving."
(Bhagavad-Gita-----9:6-----purport).

The word chandobhiḥ refers to the various Vedic literatures. The Taittirīya Upaniṣad, for example, which is a branch of the Yajur Veda, describes nature, the living entity and the Supreme Personality of Godhead.
As stated before, kṣetra is the field of activities, and there are two kinds of kṣetra-jña: the individual living entity and the supreme living entity. As stated in the Taittirīya Upaniṣad (2.9), brahma pucchaṁ pratiṣṭhā. There is a manifestation of the Supreme Lord's energy known as anna-maya, dependence upon food for existence. This is a materialistic realization of the Supreme.
(Bhagavad-Gita-----13:5-----purport).

The Vedic hymns confirm the fact that He is the origin of all living entities and the rest of all. After creation, everything rests in His omnipotence, and after annihilation everything again returns to rest in Him. These are the confirmations of Vedic hymns. Yato vā imāni bhūtāni jāyante yena jātāni jīvanti yat prayanty abhisaṁ-viśanti tad brahma tad vijijñāsasva (Taittirīya Upaniṣad 3.1).
(Bhagavad-Gita-----13:17-----purport).

In Śrīmad-Bhāgavatam it is stated that although a person may rise to the stage of impersonal Brahman, without going further, with no information of the Supreme Person, his intelligence is not perfectly clear. Therefore, in spite of being raised to the Brahman platform, there is the chance of falling down if one is not engaged in the devotional service of the Lord. In the Vedic language it is also said, raso vai saḥ, rasaṁ hy evāyaṁ labdhvānandī bhavati: "When one understands the Personality of Godhead, the reservoir of pleasure, Kṛṣṇa, he actually becomes transcendentally blissful." (Taittirīya Upaniṣad 2.7.1)
(Bhagavad-Gita-----14:27-----purport).

It appears that the great sage Atri Muni had no specific idea of the Supreme Personality of Godhead. Of course, he must have been conversant with the Vedic information that there is a Supreme Personality of Godhead who is the creator of the universe, from whom everything emanated, who maintains this created manifestation, and in whom the entire manifestation is conserved after dissolution. Yato vā imāni bhūtāni (Taittirīya Upaniṣad 3.1.1). The Vedic mantras give us information of the Supreme Personality of Godhead, so Atri Muni concentrated his mind upon that Supreme Personality of Godhead, even without knowing His name, just to beg from Him a child exactly on His level.
(Srimad Bhagavatam-----4:1:20-----purport).

The word vipaścitaḥ is explained in the Taittirīya Upaniṣad as follows: satyaṁ jñānam anantaṁ brahma. yo veda nihitaṁ guhāyāṁ parame vyoman. so 'śnute sarvān kāmān saha brahmaṇā vipaściteti. As Kṛṣṇa states in Bhagavad-gītā (7.19), bahūnāṁ janmanām ante jñānavān māṁ prapadyate: "After many births and deaths, he who is actually in knowledge surrenders unto Me." When one understands that the Lord is situated in everyone's heart and actually sees the Lord present everywhere, he has perfect knowledge.
(Srimad Bhagavatam-----5:18:36-----purport).

Devotional service is actual liberation. When one is attracted by the beauty of the Supreme Personality of Godhead and his mind is always engaged at the Lord's lotus feet, he is no longer interested in subjects that do not help him in self-realization. In other words, he loses all attraction for material activities. In the Taittirīya Upaniṣad (2.7) it is said: eṣa hy evānandayati. yadā hy evaiṣa etasmin na dṛśye 'nātmye anirukte 'nilayane 'bhayaṁ pratiṣṭhāṁ vindate 'tha so 'bhayaṁ gato bhavati. A living entity becomes established in spiritual, blissful life when he fully understands that his happiness depends on spiritual self-realization, which is the basic principle of ānanda (bliss), and when he is eternally situated in the service of the Lord, who has no other lord above Him.
(Srimad Bhagavatam-----5:19:20-----purport).

The Supreme Lord, the creator of this cosmic manifestation, knows every nook and corner of His creation. Although He is the cause of creation, there is no cause for His appearance. He is fully aware of everything. He is the Supersoul, the master of all transcendental qualities, and He is the master of this cosmic manifestation in regard to bondage to the conditional state of material existence and liberation from that bondage."
Similarly, in the Taittirīya Upaniṣad (2.8) it is said:
bhīṣāsmād vātaḥ pavate
bhīṣodeti sūryaḥ
bhīṣāsmād agniś candraś ca
mṛtyur dhāvati pañcamaḥ
"It is out of fear of the Supreme Brahman that the wind is blowing, out of fear of Him that the sun regularly rises and sets, and out of fear of Him that fire acts. It is only due to fear of Him that death and Indra, the King of heaven, perform their respective duties."
(Srimad Bhagavatam-----5:20:5-----purport).

One may argue, "When we analyze the body we find a head, hands, legs, a belly, blood, bones, urine, stool and so on, but after everything is considered, where is the existence of the soul?" A sober man, however, avails himself of this Vedic instruction:
yato vā imāni bhūtāni jāyante; yena jātāni jīvanti; yat prayanty abhisaṁviśanti; tad vijijñāsasva; tad brahmeti.
(Taittirīya Upaniṣad 3.1.1)
Thus he can understand that the head, hands, legs and indeed the entire body have grown on the basis of the soul. If the soul is within, the body, head, hands and legs grow, but otherwise they do not. A dead child does not grow up, for the soul is not present.
(Srimad Bhagavatam-----7:7:24-----purport).

The Lord comes personally to instruct us how to be happy, and only fools and rascals do not see by intelligence this supreme authority, the Supreme Person. In the śruti-mantra it is said:
bhīṣāsmād vātaḥ pavate
bhīṣodeti sūryaḥ
bhīṣāsmād agniś candraś ca
mṛtyur dhāvati pañcamaḥ
(Taittirīya Upaniṣad 2.8)
It is out of fear of the Supreme Personality of Godhead that the wind is blowing, that the sun is distributing heat and light, and that death is chasing everyone.
(Srimad Bhagavatam-----8:2:33-----purport).

Lord Śrī Kṛṣṇa wants to make known to all the conditioned souls that He is more attracted by rāga-bhakti than vidhi-bhakti, or devotional service under scheduled regulations. It is said in the Vedas (Taittirīya Up. 2.7), raso vai saḥ: the Absolute Truth is the reservoir for all kinds of reciprocal exchanges of loving sentiments. He is also causelessly merciful, and He wants to bestow upon us this privilege of rāga-bhakti. Thus He appeared by His own internal energy. He was not forced to appear by any extraneous force.
(Sri Caitanya Caritamrta-----1:4:15-16-----purport).

It is to be concluded that the entire cosmic manifestation is a transformation of the energy of the Supreme Lord, not of the Supreme Lord or Absolute Truth Himself, who always remains the same. The material world and the living entities are transformations of the energy of the Lord, the Absolute Truth or Brahman, who is the original source. In other words, the Absolute Truth, Brahman, is the original ingredient, and the other manifestations are transformations of this ingredient. This is also confirmed in the Taittirīya Upaniṣad(3.1): yato vā imāni bhūtāni jāyante. "This entire cosmic manifestation is made possible by the Absolute Truth, the Supreme Personality of Godhead." In this verse it is indicated that Brahman, the Absolute Truth, is the original cause and that the living entities (jīvas) and the cosmic manifestation are effects of this cause. The cause being a fact, the effects are also factual. They are not illusion.
(Sri Caitanya Caritamrta-----1:7:121-----purport).

One may argue, "If the Supreme Personality of Godhead is completely spiritual, how is it possible for Him to be the origin of creation and have within Himself both material and spiritual energies?" To answer this challenge, Śrīpāda Rāmānujācārya quotes a mantra from the Taittirīya Upaniṣad (3.1) that states:
yato vā imāni bhūtāni jāyante yena jātāni jīvanti yat prayanty abhisaṁviśanti
This mantra confirms that the entire cosmic manifestation emanates from the Absolute Truth, rests upon the Absolute Truth and after annihilation again reenters the body of the Absolute Truth, the Supreme Personality of Godhead. The living entity is originally spiritual, and when he enters the spiritual world or the body of the Supreme Lord, he still retains his identity as an individual soul. In this connection Śrīpāda Rāmānujācārya gives the example that when a green bird enters a green tree it does not become one with the tree: it retains its identity as a bird, although it appears to merge with the greenness of the tree. To give another example, an animal that enters a forest keeps its individuality, although apparently the beast merges with the forest. Similarly, in material existence, both the material energy and the living entities of the marginal potency maintain their individuality. Thus although the energies of the Supreme Personality of Godhead interact within the cosmic manifestation, each keeps its separate individual existence. Merging with the material or spiritual energies, therefore, does not involve loss of individuality. According to Śrī Rāmānujapāda's theory of Viśiṣṭādvaita, although all the energies of the Lord are one, each keeps its individuality (vaiśiṣṭya).
(Sri Caitanya Caritamrta-----1:7:121-----purport).

The falsity of Śrīpāda Śaṅkarācārya's explanation of vivarta-vāda and pariṇāma-vāda has been detected by the Vaiṣṇava ācāryas, especially Jīva Gosvāmī, whose opinion is that actually Śaṅkara did not understand the Vedānta-sūtra. In Śaṅkara's explanation of one sūtra, ānanda-mayo ’bhyāsāt, he has interpreted the affix mayaṭ with such word jugglery that this very explanation proves that he had little knowledge of the Vedānta-sūtra but simply wanted to support his impersonalism through the aphorisms of the Vedānta philosophy. Actually, however, he failed to do so because he could not put forward strong arguments. In this connection, Śrīla Jīva Gosvāmī cites the phrase brahma pucchaṁ pratiṣṭhā (Taittirīya Up. 2.5), which gives Vedic evidence that Brahman is the origin of everything. In explaining this verse, Śrīpāda Śaṅkarācārya interpreted various Sanskrit words in such a way that he implied, according to Jīva Gosvāmī, that Vyāsadeva had very little knowledge of higher logic. Such unscrupulous deviation from the real meaning of the Vedānta-sūtra has created a class of men who by word jugglery try to derive various indirect meanings from the Vedic literatures, especially the Bhagavad-gītā.
(Sri Caitanya Caritamrta-----1:7:127-----purport).

In the Taittirīya Upaniṣad (3.1) it is said, yato vā imāni bhūtāni jāyante: "The entire material cosmic manifestation is born of the Supreme Brahman."
(Sri Caitanya Caritamrta-----2:6:143-----purport).

Śrīla Bhaktivinoda Ṭhākura states in his Amṛta-pravāha-bhāṣya that according to the injunction of the Upaniṣads ("the Supreme Absolute Truth is He from whom everything emanates"), it is understood that the whole cosmic manifestation emanated from Brahman, the Supreme Absolute Truth. The creation subsists by the energy of the Supreme Brahman and, after annihilation, merges into the Supreme Brahman. From this we can understand that the Absolute Truth can be categorized in three cases—ablative, instrumental and locative. According to these three cases, the Absolute Truth is positively personified. In this connection, Śrīla Bhaktisiddhānta Sarasvatī quotes the Aitareya Upaniṣad (1.1.1): ātmā vā idam eka evāgra āsīn nānyat kiñcana miṣat sa īkṣata lokān nu sṛjā iti. Similarly, in the Śvetāśvatara Upaniṣad (4.9) it is stated:
chandāṁsi yajñāḥ kratavo vratāni
bhūtaṁ bhavyaṁ yac ca vedā vadanti
yasmān māyī sṛjate viśvam etat
tasmiṁś cānyo māyayā sanniruddhaḥ
And in the Taittirīya Upaniṣad (3.1): yato vā imāni bhūtāni jāyante, yena jātāni jīvanti, yat prayanty abhisaṁviśanti, tad vijijñāsasva tad brahma. This was the answer given by father Varuṇa when questioned by his son Vāruṇi Bhṛgu about the Absolute Truth. In this mantra, the word yataḥ, the Absolute Truth from which the cosmic manifestation has emanated, is in the ablative case; that Brahman by which this universal creation is maintained is in the instrumental case (yena); and that Brahman into which the whole cosmic manifestation merges is in the locative case (yat or yasmin). It is stated in Śrīmad-Bhāgavatam (S.B.1:5:20):
idaṁ hi viśvaṁ bhagavān ivetaro
yato jagat-sthāna-nirodha-sambhavāḥ
"The entire universal creation is contained in the gigantic form of the Supreme Personality of Godhead. Everything emanates from Him, everything rests in His energy, and after annihilation everything merges into His person."
(Sri Caitanya Caritamrta-----2:6:144-----purport).

The first verse of the Brahma-sūtra is athāto brahma jijñāsā: "We must now inquire into the Absolute Truth." The second verse immediately answers, janmādy asya yataḥ: "The Absolute Truth is the original source of everything." Janmādy asya yataḥ does not suggest that the original person has been transformed. Rather, it clearly indicates that He produces this cosmic manifestation through His inconceivable energy. This is also clearly explained in the Bhagavad-gītā (10.8), where Kṛṣṇa says, mattaḥ sarvaṁ pravartate: "From Me, everything emanates." This is also confirmed in the Taittirīya Upaniṣad (3.1.1): yato vā imāni bhūtāni jāyante. "The Supreme Absolute Truth is that from which everything is born." Similarly, in the Muṇḍaka Upaniṣad (1.1.7) it is stated, yathorṇa-nābhiḥ sṛjate gṛhṇate ca: "(The Lord creates and destroys the cosmic manifestation) as a spider creates a web and draws it back within itself." All of these sūtras indicate the transformation of the Lord's energy. It is not that the Lord undergoes direct transformation, which is called pariṇāma-vāda. However, being very anxious to protect Śrīla Vyāsadeva from criticism, Śaṅkarācārya became a pseudo gentleman and put forward his theory of illusion (vivarta-vāda). Śaṅkarācārya concocted this meaning of pariṇāma-vāda, and by word jugglery he endeavored very hard to establish pariṇāma-vāda as vivarta-vāda.
(Sri Caitanya Caritamrta-----2:6:172-----purport).

The Supreme Absolute Truth has His inconceivable potency, out of which this cosmos has been manifested. In other words, the Supreme Absolute Truth is the ingredient, and the living entity and cosmic manifestation are the by-products. In the Taittirīya Upaniṣad it is clearly stated, yato vā imāni bhūtāni jāyante: "The Absolute Truth is the original reservoir of all ingredients, and this material world and its living entities are produced from those ingredients."
(Teachings of Lord Caitanya).

According to a mantra in Taittirīya Upaniṣad (yato vā imāni bhūtāni jāyante) this cosmic manifestation is but an emanation from the Supreme Absolute Truth, and it rests in the Supreme Absolute Truth. The Absolute Truth has been called the ablative, causative and locative performer. Thus as a performer, He is the Supreme Personality of Godhead, for these are symptoms of personality. As the ablative performer of this cosmic manifestation, all thinking, feeling and willing come from Him. Without thinking, feeling and willing, there is no possibility of arrangement and design in the cosmic manifestation. Then again, He is causative, for He is the original designer of the cosmos. And He is locative: that is, everything is resting in His energy. These attributes are all clearly attributes of personality.
(Teachings of Lord Caitanya).

The personified Vedas continued to pray, "Dear Lord, considering all points of view, if a person has to worship someone superior to himself, then just out of good behavior he should stick to the worship of Your lotus feet because You are the ultimate controller of creation, maintenance and dissolution. You are the controller of the three worlds, Bhūḥ, Bhuvaḥ and Svaḥ; You are the controller of the fourteen upper and lower worlds; and You are the controller of the three material qualities. Demigods and persons advanced in spiritual knowledge always hear and chant about Your transcendental pastimes because this process has the specific potency of nullifying the accumulated results of sinful life. Intelligent persons factually dip into the ocean of Your nectarean activities and very patiently hear about them. Thus they are immediately freed from the contamination of the material qualities; they do not have to undergo severe penances and austerities for advancement in spiritual life. This chanting and hearing of Your transcendental pastimes is the easiest process for self-realization. Simply by submissive aural reception of the transcendental message, one's heart is cleansed of all dirty things. Thus Kṛṣṇa consciousness becomes fixed in the heart of a devotee." The great authority Bhīṣmadeva has also given the opinion that this process of chanting and hearing about the Supreme Personality of Godhead is the highest religious process. And the Taittirīya Upaniṣad says that worship of the Supreme Personality of Godhead is the essence of all Vedic ritualistic performances.
(Krsna Book).