Chandogya Upanishad 7.13.1

7.13.1

smaro vāvākāśād (S ) \
tasmād yady api bahava āsīrann a smaranto naiva te kaṃcana śṛṇuyur na manvīran na (S ) \
yadā vāva te smareyur atha śṛṇuyur atha manvīrann atha (S ) \
smareṇa vai putrān vijānāti smareṇa paśūn \
smaram upāssveti \\713.1\

'Memory surely is greater than Ākāśa. Therefore, even if many persons should assemble and if they should have no memory, they surely would not hear any sound, they would not think, they would not know. But surely, should they have memory, then they would hear, then they would think, then they would know. Through memory, indeed, one discerns one's sons, through memory one's cattle. Worship memory.