One verse

Srimad Bhagavatam 12.4.30

12.4.30

न हि सत्यस्य नानात्वमविद्वान् यदि मन्यते । नानात्वं छिद्रयोर्यद्वज्ज्योतिषोर्वातयोरिव ॥ ३० ॥

na hi satyasya nānātvam avidvān yadi manyate nānātvaṁ chidrayor yadvaj jyotiṣor vātayor iva

na
there is no
hi
indeed
satyasya
of the Absolute Truth
nānātvam
duality
avidvān
a person not in true knowledge
yadi
if
manyate
he thinks
nānātvam
the duality
chidrayoḥ
of the two skies
yadvat
just as
jyotiṣoḥ
of the two celestial lights
vātayoḥ
of the two winds
iva
as

There is no material duality in the Absolute Truth. The duality perceived by an ignorant person is like the difference between the sky contained in an empty pot and the sky outside the pot, or the difference between the reflection of the sun in water and the sun itself in the sky, or the difference between the vital air within one living body and that within another body.