Vanadurgā Upaniṣad 3.7.p27

3.7.p27

manomadhyagato nādo nādamadhyagatāḥ kalāḥ |
kalāmadhyagato jīvo jīvamadhyagatā parā |
jīvaḥ paraḥ paro jīvaḥ sarva brahmeti bhāvayet ||

within the mind is the primordial sound; within the primordial sound are the fractional powers; / within the fractional powers is the individual soul; within the individual soul is the supreme reality; / the individual soul is the supreme reality, the supreme reality is the individual soul—one should contemplate all as Brahman.