One verse

Srimad Bhagavatam 12.6.40-41

12.6.40-41

श‍ृणोति य इमं स्फोटं सुप्तश्रोत्रे च शून्यद‍ृक् । येन वाग् व्यज्यते यस्य व्यक्तिराकाश आत्मन: ॥ ४० ॥ स्वधाम्नो ब्राह्मण: साक्षाद् वाचक: परमात्मन: । स सर्वमन्त्रोपनिषद्वेदबीजं सनातनम् ॥ ४१ ॥

śṛṇoti ya imaṁ sphoṭaṁ supta-śrotre ca śūnya-dṛk yena vāg vyajyate yasya vyaktir ākāśa ātmanaḥ sva-dhāmno brahmaṇaḥ sākṣād vācakaḥ paramātmanaḥ sa sarva-mantropaniṣad veda-bījaṁ sanātanam

śṛṇoti
hears
yaḥ
who
imam
this
sphoṭam
unmanifest and eternal subtle sound
supta-śrotre
when the sense of hearing is asleep
ca
and
śūnya-dṛk
devoid of material sight and other sensory functions
yena
by which
vāk
the expanse of Vedic sound
vyajyate
is elaborated
yasya
of which
vyaktiḥ
the manifestation
ākāśe
in the sky (of the heart)
ātmanaḥ
from the soul
sva-dhāmnaḥ
who is His own origin
brahmaṇaḥ
of the Absolute Truth
sākṣāt
directly
vācakaḥ
the designating term
parama-ātmanaḥ
of the Supersoul
saḥ
that
sarva
of all
mantra
Vedic hymns
upaniṣat
the secret
veda
of the Vedas
bījam
the seed
sanātanam
eternal

This oṁkāra, ultimately nonmaterial and imperceptible, is heard by the Supersoul without His possessing material ears or any other material senses. The entire expanse of Vedic sound is elaborated from oṁkāra, which appears from the soul, within the sky of the heart. It is the direct designation of the self-originating Absolute Truth, the Supersoul, and is the secret essence and eternal seed of all Vedic hymns.