Ashtavakra Gita · Verse 1.19 · Ashtavakra speaks

Just as a mirror exists within and all around the image reflected in it, so the Supreme Lord exists inside and outside this body.
यथैवादर्शमध्यस्थे रूपेऽन्तः परितस्तु सः ।तथैवाऽस्मिन् शरीरेऽन्तः परितः परमेश्वरः ॥ १-१९॥
yathaivādarśamadhyasthe rūpe'ntaḥ paritas tu saḥ |tathāivā'smin śarīre'ntaḥ parataḥ parameśvaraḥ ||1-19||

Word by word

यथैव

yathaiva

just as, even as

indeclinable comparative particle

आदर्श

ādarśa

mirror

noun, masculine (compound member)

रूपे

rūpe

in the image, in the form

noun, neuter, locative singular

अन्तः

antaḥ

inside, within

indeclinable adverb

परितः

paritaḥ

all around, outside

indeclinable adverb

परमेश्वरः

parameśvaraḥ

the Supreme Lord, the ultimate Reality

compound noun (parama + īśvara), masculine, nominative singular

The image in a mirror has no real existence — only the mirror exists. Body, mind etc. are similarly superimposed on the Self and cannot affect it, as a reflection cannot affect the mirror.

शरीरे

śarīre

in this body

noun, neuter, locative singular