dānaṁ sva-dharmo niyamo yamaś ca
 śrutaṁ ca karmāṇi ca sad-vratāni
sarve mano-nigraha-lakṣaṇāntāḥ
 paro hi yogo manasaḥ samādhiḥ

Charity, prescribed duties, observance of major and minor regulative principles, hearing from scripture, pious works and purifying vows all have as their final aim the subduing of the mind. Indeed, concentration of the mind on the Supreme is the highest yoga (Śrīmad-Bhāgavatam 11.23.45).

“sarve mano-nigraha-lakṣaṇāntāḥ. Not everyone is able to understand that unless the mind is controlled, you cannot even cook or cannot hear or read. You cannot be a student, because whatever the teacher will say, you will not understand, because your mind will be roaming. So in whatever department you will go, you must control your mind, because without controlling it you cannot do anything. But how to control it? This is the problem.
There were some rats who wanted to control a cat who was always chasing them. They were discussing among themselves, “This cat is always coming without making any noise and therefore is killing so many of us. What can we do to solve this problem?” Then one of them said, “You tie a bell on his neck, then we will hear when he is coming.” “Yes, but who will tie it? Whoever will do it, will be eaten first!” So nobody came forward. This is our position. Everybody wants to control the mind, but we have to be very sincere and serious in thinking how to do it. If you control the mind, all problems will be automatically solved. All problems.”

— Śrīla Bhakti Vaibhāva Purī Mahārāja