In the Gita Arjuna asks Krishna, β€œIs the mind so easily controllable? Even an elephant cannot drag one as the mind does; it is the nursery of waywardness, and its defiance, determination and obstinacy are very powerful. The mind will never halt at one place. Taming the mind is like capturing the wind or bundling up water. How can anyone control the mind or begin any spiritual practice with such a mind?” Krishna broke into a smile on hearing these words and said, "Arjuna! You have described the mind and know its nature very well. But it is not an impossible task; the mind can certainly be mastered. By systematic practice (abhyasa) and by relentless inquiry (vichara) and detachment (vairagya) - the mind definitely can be conquered. There is no task that cannot be accomplished by steady practice. Place faith in the Lord and practice with the firm belief that you have the power and the grace - then all tasks will become easy.”  - Geetha Vahini, Ch 11.

Swami Talking about the nature of mind

The way to control it...