Chandogya Upanishad 7.13

smaro vāvākāśād bhūyaḥ tasmād yady api bahava āsīrann asmaranto naiva te kaṃcana śṛṇuyur na manvīran na vijānīran yadā vāva te smareyur atha śṛṇuyur atha manvīrann atha vijānīran smareṇa vai putrān vijānāti smareṇa paśūn smaram upāssveti

'Memory (smara) is better than ether. Therefore where many are assembled together, if they have no memory, they would hear no one, they would not perceive, they would not understand. Through memory we know our sons, through memory our cattle. Meditate on memory.

sa yaḥ smaraṃ brahmety upāste yāvat smarasya gataṃ tatrāsya yathākāmacāro bhavati yaḥ smaraṃ brahmety upāste asti bhagavaḥ smarād bhūya iti smarād vāva bhūyo 'stīti tan me bhagavān bravītv iti

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