Taittirīyopaniṣat 02.12

तस्माद्वा एतस्मात् विज्ञानमयात्। अन्योऽन्तर आत्माऽऽनन्दमयः। तेनैष पूर्णः। स वा एष पुरुषविध एव। तस्य पुरुषविधताम्। अन्वयं पुरुषविधः। तस्य प्रियमेव शिरः। मोदो दक्षिणः पक्षः। प्रमोद उत्तरः पक्षः। आनन्द आत्मा। ब्रह्म पुच्छं प्रतिष्ठा॥

Therefore, beyond this vijñānamaya realm, there is another inner essence, the ānandamaya realm, composed of bliss. By this, it is complete. This is verily of the form of a person. Its personhood is continuous. It is established thus: the head is what is dear, the right wing is joy, the left wing is delight, its essence is bliss, and Brahma, the manifested universe, is the tail.

तदप्येष श्लोको भवति। असन्नेव स भवति। असद् ब्रह्मेति वेद चेत्। अस्ति ब्रह्मेति चेद्वेद। सन्तमेनं ततो विदुरिति। तस्यैष एव शारीर आत्मा। यः पूर्वस्य ॥१२॥

There is also this verse: "He indeed becomes non-existent (in the physical realm), if one knows Brahman as non-being; or if one knows Brahman as being, then they know him as existent. Of him, this is indeed the embodied Ātmān, who belongs to the former."

Taittirīya Bhāshya 02.12

Testimonial continues elaborating on the five realms and the forms of the Lord established in each. It concludes with two important notes: (i) Just as the body is outside and the embodied being is inside, so too Lord Viṣṇu is remembered as existing both externally and internally. (ii) Those who claim only five forms of Brahman exist and individual being or anything else does not exist are abodes of non-existence and darkness. But those who know the supreme Brahman, distinct from the individual being, are to be regarded as truly existent; indeed, they alone are certainly fit for liberation.

तस्मिन्नानन्दरूपोऽसौ स्थितो नारायणस्सदा। शिरः प्रिये स्थितं तस्य परेयं प्रियनामकम्॥

There, Lord Nārāyaṇa, who is of the nature of bliss, always abides. O beloved, on his head is placed this supreme entity called Priya.

मोदप्रमोदयोर्बाहू मोदनाच्च प्रमोदनात्। मोदप्रमोदनामानावानन्दस्त्वाततत्वतः॥

The arms of Moda and Pramoda originate from Modana i.e. joy, and Pramodana i.e. over joyed ecstasy. Those so-called Moda and Pramoda arise from you, named Ānanda, the bliss, but not from those who lack that true nature.

मध्यमानन्दसंस्थं च ब्रह्मसृष्ट्या तु बृंहयेत्। पुच्छं प्रधानवायौ च ब्रह्माख्ये संस्थितं सदा। अभेदोऽप्यविशेषोऽपि परमैश्वर्ययोगतः॥

One should expand the bliss that is situated in the middle through the creation of Brahma. The tail is always established in the chief vital air, called Brahma. Even non-difference and non-distinction arise due to union with supreme sovereignty.

देहदेहिवदेवासौ पञ्चधाऽवस्थितो हरिः। बहिःस्थो देहवद्विष्णुरन्तस्थो देहिवत् स्मृतः॥ अन्तर्व्याप्ति विशेषेण न त्वशक्तत्वतो बहिः।

Lord Hari (Viṣṇu) is said to be present in five ways: just as the body is outside and the embodied being is inside, so too Lord Viṣṇu is remembered as existing both externally and internally. Internal pervasion is due to speciality, and not due to incapacity (to sustain) outside.

सर्वेऽपि पुरुषाकाराः उत्तरात् पूर्वसम्भवाः॥ उत्तरैः पूरिताः पूर्वे निश्छिद्रत्वेन सर्वशः। अत्तृत्वं च प्रणेतृत्वं बोधो विविधवेत्तृता। आनन्दश्च यतः पूर्णस्ततोऽन्नादिमयाः स्मृताः । अत्त्यादिदास्ते प्रत्येकं सर्वे सर्वगुणा अपि॥

All human forms arise from the former through the latter. The successors completely fill the predecessors without any gaps. The states of being an eater, initiator, knower of various kinds, and bliss — since he is full; therefore those composed of 'annādimayāḥ' i.e. food, and so on are known as such. All those who are eaters and so on, each one, possess all qualities as well.

नामभेदस्ततस्तूक्तः सर्वनामवतामपि। पञ्चरूपं च तद् ब्रह्म जीवादन्यन्न विद्यते॥ इति ये तु विजानन्ति तेऽसन्तस्तमआलयाः। जीवादन्यत् परं ब्रह्म पञ्चरूपं च ये विदुः॥ सन्तस्त इति विज्ञेया मोक्षयोग्या हि ते ध्रुवम्॥

Thus, the distinction of names is stated, even for all names. "There are five forms of that Brahman — apart from that, individual being and anything else does not exist." - Those who know only thus are abodes of non-existence and darkness. But those who know the supreme Brahman, distinct from the individual being and five-formed, are to be regarded as truly existent; indeed, they alone are certainly fit for liberation.