Śrīmad-Bhāgavatam · Text 10.87.33
Who is speaking and story frame
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
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.
Read the purport on Vedabase.ioFrom Canto 10, chapter 14 onward, the translation and purports were completed by Śrīla Prabhupāda's disciples after his departure, and published by the Bhaktivedanta Book Trust.