One verse

Srimad Bhagavatam 10.87.33

10.87.33

विजितहृषीकवायुभिरदान्तमनस्तुरगं य इह यतन्ति यन्तुमतिलोलमुपायखिद: । व्यसनशतान्विता: समवहाय गुरोश्चरणं वणिज इवाज सन्त्यकृतकर्णधरा जलधौ ॥ ३३ ॥

vijita-hṛṣīka-vāyubhir adānta-manas tura-gaṁ ya iha yatanti yantum ati-lolam upāya-khidaḥ vyasana-śatānvitāḥ samavahāya guroś caraṇaṁ vaṇija ivāja santy akṛta-karṇa-dharā jaladhau

vijita
conquered
hṛṣīka
with senses
vāyubhiḥ
and vital air
adānta
not brought under control
manaḥ
the mind
tura-gam
(which is like) a horse
ye
those who
iha
in this world
yatanti
endeavor
yantum
to regulate
ati
very
lolam
unsteady
upāya
by their various methods of cultivation
khidaḥ
distressed
vyasana
disturbances
śata
by hundreds
anvitāḥ
joined
samavahāya
abandoning
guroḥ
of the spiritual master
caraṇam
the feet
vaṇijaḥ
merchants
iva
as if
aja
O unborn one
santi
they are
akṛta
having not taken
karṇa-dharāḥ
a helmsman
jala-dhau
on the ocean

The mind is like an impetuous horse that even persons who have regulated their senses and breath cannot control. Those in this world who try to tame the uncontrolled mind, but who abandon the feet of their spiritual master, encounter hundreds of obstacles in their cultivation of various distressful practices. O unborn Lord, they are like merchants on a boat in the ocean who have failed to employ a helmsman.