Chandogya Upanishad 7.7

vijñānaṃ vāva dhyānād bhūyaḥ vijñānena vā ṛgvedaṃ vijānāti yajurvedaṃ sāmavedam ātharvaṇaṃ caturtham itihāsapurāṇaṃ pañcamaṃ vedānāṃ vedaṃ pitryaṃ rāśiṃ daivaṃ nidhiṃ vākovākyam ekāyanaṃ devavidyāṃ brahmavidyāṃ bhūtavidyāṃ kṣatravidyāṃ nakṣatravidyāṃ sarpadevajanavidyāṃ divaṃ ca pṛthivīṃ ca vāyuṃ cākāśaṃ cāpaś ca tejaś ca devāṃś ca manuṣyāṃś ca paśūṃś ca vayāṃsi ca tṛṇavanaspatīñchvāpadāny ā kīṭapataṅgapipīlakam dharmaṃ cādharmaṃ ca satyaṃ cānṛtaṃ ca sādhu cāsādhu ca hṛdayajñaṃ cāhṛdayajñaṃ cānnaṃ ca rasaṃ cemaṃ ca lokam amuṃ ca vijñānenaiva vijānāti vijñānam upāssveti

'Understanding (vigñâna) is better than reflection. Through understanding we understand the Rig-veda, the Yagur-veda, the Sâma-veda, and as the fourth the Âtharvana, as the fifth the tihâsapurâna, the Veda of the Vedas, the Pitrya, the Râsi, the Daiva, the Nidhi, the Vâkovâkya, the Ekâyana, the Deva-vidyâ, the Brahma-vidyâ, the Bhûta-vidyâ, the Kshatra-vidyâ, the Nakshatra-vidyâ, the Sarpa and Devagana-vidyâ, heaven, earth, air, ether, water, fire, gods, men, cattle, birds, herbs, trees, all beasts down to worms, midges, and ants; what is right and what is wrong; what is true and what is false; what is good and what is bad; what is pleasing and what is not pleasing; food and savour, this world and that, all this we understand through understanding. Meditate on understanding.

sa yo vijñānaṃ brahmety upāste vijñānavato vai sa lokāñ jñānavato 'bhisidhyati yāvad vijñānasya gataṃ tatrāsya yathākāmacāro bhavati yo vijñānaṃ brahmety upāste asti bhagavo vijñānād bhūya iti vijñānād vāva bhūyo 'stīti tan me bhagavān bravītv iti

'He who meditates on understanding as Brahman, reaches the worlds where there is understanding and knowledge; he is, as it were, lord and master as far as understanding reaches—he who meditates on understanding as Brahman.' 'Sir, is there something better than understanding?' 'Yes, there is something better than understanding.' 'Sir, tell it me.'