One verse

Srimad Bhagavatam 7.7.21

7.7.21

स्वर्णं यथा ग्रावसु हेमकार: क्षेत्रेषु योगैस्तदभिज्ञ आप्नुयात् । क्षेत्रेषु देहेषु तथात्मयोगै- रध्यात्मविद् ब्रह्मगतिं लभेत ॥ २१ ॥

svarnam yatha gravasu hema-karah ksetresu yogais tad-abhijna apnuyat ksetresu dehesu tathatma-yogair adhyatma-vid brahma-gatim labheta

svarnam
gold
yatha
just as
gravasu
in the stones of gold ore
hema-karah
the expert who knows about gold
ksetresu
in the gold mines
yogaih
by various processes
tat-abhijnah
an expert who can understand where gold is
apnuyat
very easily obtains
ksetresu
within the material fields
dehesu
the human bodies and all the rest of the 8,400,000 different bodily forms
tatha
similarly
atma-yogaih
by spiritual processes
adhyatma-vit
one who is expert in understanding the distinction between spirit and matter
brahma-gatim
perfection in spiritual life
labheta
may obtain

An expert geologist can understand where there is gold and by various processes can extract it from the gold ore. Similarly, a spiritually advanced person can understand how the spiritual particle exists within the body, and thus by cultivating spiritual knowledge he can attain perfection in spiritual life. However, as one who is not expert cannot understand where there is gold, a foolish person who has not cultivated spiritual knowledge cannot understand how the spirit exists within the body.