The mind is cancala, flickering, and it changes very strongly. Therefore Arjuna admitted that controlling the mind is not at all possible; this would be as difficult as controlling the wind. For example, if one were in a boat moving according to the wind on a river or the sea, and the wind were uncontrollable, the tilting boat would be very much disturbed and extremely difficult to control. It might even capsize. Therefore, in the bhava-samudra, the ocean of mental speculation and transmigration to different types of bodies, one must first control the mind.
Reference: The mind is cancala, flickering, and it changes very strongly. Therefore Arjuna admitted that controlling the mind is
