Maitri (Maitrāyaṇīya) Upaniṣad 6.17

6.17

brahma ha vā idamagra āsīt eko'nantaḥ prāgananto dakṣiṇo'nantaḥ pratīcyananta udīcyananta ūrdhvān cā'vān ca sarvato'nantaḥ na hyāsya prācyādi diśaḥ kalpante'tha tiryagvān cordhvaṃ vā anūhya eṣa paramātmā'parimito'tarkyo'cintya eṣa ākāśātmā evaiṣa kṛtsnakṣaya eko jāgartīti etasmādākāśādeṣa khalvidaṃ cetāmātraṃ bodhayati anenaiva cedam dhyāyate asmin ca pratyastaṃ yāti asyaitadbhāsvaraṃ rūpaṃ yadamuṣminnāditye tapati agnau cādhumake yajjyotiścitrataramudarasto'tha vā yaḥ pacatyannam ityevaṃ hyāha
yaścaiṣo'gnau yaścāyaṃ hṛdaye yaścāsāvāditye sa eṣa ekā ityekasya haikatvameti ya evaṃ veda ||

17. Verily, in the beginning this world was Brahma, the limitless One—limitless to the east, limitless to the south, limitless to the west, limitless to the north, and above and below, limitless in every direction. Truly, for him east and the other directions exist not, nor across, nor below, nor above.

Incomprehensible is that supreme Soul (Ātman), unlimited, unborn, not to be reasoned about, unthinkable—He whose soul is space (ākāśātman)! In the dissolution of the world He alone remains awake. From that space He, assuredly, awakes this world, which is a mass of thought. It is thought by Him, and in Him it disappears.

His is that shining form which gives heat in yonder sun and which is the brilliant light in a smokeless fire, as also the fire in the stomach which cooks food. For thus has it been said: ‘He who is in the fire, and he who is here in the heart, and he who is yonder in the sun—he is one.’

To the unity of the One goes he who knows this.