Chāndogya Upaniṣad 6.11.3

6.11.3

evam eva khalu somya viddhīti ha uvāca \
jīvāpetaṃ vāva kiledaṃ mriyate na jīvo mriyata iti \
sa ya eṣo 'ṇimaitad ātmyam idaṃ sarvam \
tat satyam \
sa ātmā \
tat tvam asi śvetaketo iti \
bhūya eva mā bhagavān vijñāpayatv iti \
tathā somyeti hovāca \\611.3\

3. ‘Verily, indeed, when life has left it, this body dies. The life does not die. That which is the finest essence—this whole world has that as its soul. That is Reality. That is Ātman (Soul). That art thou, Śvetaketu.’ ‘Do you, Sir, cause me to understand even more.’ ‘So be it, my dear,’ said he.

2. If the life leaves one branch of it, then it dries up. It leaves a second; then that dries up. It leaves a third; then that dries up. It leaves the whole; the whole dries up. Even so, indeed, my dear, understand,’ said he.