Bṛhadāraṇyaka Upaniṣad ("Great Forest Teaching") 2.3

2.3.1

dve vāva brahmaṇo rūpe mūrtaṃ caivāmūrtaṃ ca martyaṃ cāmṛtaṃ ca sthitaṃ ca yacca sacca tyacca

There are two forms of Brahman, the material and the immaterial, the mortal and the immortal, the solid and the fluid, sat (being) and tya (that), (i.e. sat-tya, true).

2.3.2

tadetanmūrtaṃ yadanyadvāyoścāntarikṣāccaitanmartyametatsthitametatsattasyaitasya mūrtasyaitasya martyasyaitasya sthitasyaitasya sata eṣa raso ya eṣa tapati satohyeṣa rasaḥ

Everything except air and sky is material, is mortal, is solid, is definite. The essence of that which is material, which is mortal, which is solid, which is definite is the sun that shines, for he is the essence of sat (the definite).

2.3.3

athāmūrtaṃ vāyuścāntarikṣaṃ caitadamṛtametadyadetattyantasyai tasyaitasyāmūrtasyaitasyāmṛtasyaitasya yata etasya tyasyaiṣa raso ya eṣa etasminmaṇḍale puruṣastyasya hyeṣa rasa ityadhidaivatam

But air and sky are immaterial, are immortal, are fluid, are indefinite. The essence of that which is immaterial, which is immortal, which is fluid, which is indefinite is the person in the disk of the sun, for he is the essence of tyad (the indefinite). So far with regard to the Devas.

2.3.4

athādhyātmamidameva mūrtaṃ yadanyatprāṇācca yaścāyamantarātmannākāśa etanmartyametatsthitametatsattasyaitasya mūrtasyaitasyamartyasyaitasya sthitasyaitasya sata eṣa raso yaccakṣuḥ sato hyeṣa rasaḥ

Now with regard to the body. Everything except the breath and the ether within the body is material, is mortal, is solid, is definite. The essence of that which is material, which is mortal, which is solid, which is definite is the Eye, for it is the essence of sat (the definite).

2.3.5

athāmūrtaṃ prāṇaśca yaścāyamantarātmannākāśa etadamṛtametadyadetattyaṃ tasyaitasyāmūrtasyaitasyāmṛtasyaitasya yata etasya tyasyaiṣa raso yo'yaṃ dakṣiṇe'kṣanpuruṣastyasya hyeṣa rasaḥ

But breath and the ether within the body are immaterial, are immortal, are fluid, are indefinite. The essence of that which is immaterial, which is immortal, which is fluid, which is indefinite is the person in the right eye, for he is the essence of tyad (the indefinite).

2.3.6

tasya haitasya puruṣasya rūpaṃ yathā māhārajanaṃ vāso yathāpāṇḍvāvikaṃ yathendragopo yathāgnyarciryathā puṇḍarīkaṃ yathā sakṛdvidyuttam̐ sakṛdvidyutteva ha vā asya śrīrbhavati ya evaṃ vedāthāta ādeśo neti neti na hyetasmāditi netyanyatparamastyatha nāmadheyam̐ satyasya satyamiti prāṇā vai satyaṃ teṣāmeṣa satyam

And what is the appearance of that person? Like a saffron-coloured raiment, like white wool, like cochineal, like the flame of fire, like the white lotus, like sudden lightning. He who knows this, his glory is like unto sudden lightning.
Next follows the teaching (of Brahman) by No, no! for there is nothing else higher than this (if one says): 'It is not so.' Then comes the name 'the True of the True,' the senses being the True, and he (the Brahman) the True of them.

2.3.6.p1

iti dvitīyādhyāye tṛtīyaṃ brāhmaṇam