Mind

तश्चञ्चला वृत्या चिन्तानिचयचञ्चुरम् |
धृतिं बन्धाति नैकत्र पञ्जरे केसरी यथा || – श्री वशिष्ठदर्शनं (१-१६-१०)
Meaning : The mind expert in its collection of sorrowfull thoughts does not fasten its hold on one place because of its fichle condition just as a lion in a cage .
Implied meaning : The main function of mind is to think, in fact, the congregation of thoughts is called mind hence as per its attribute it will function. The mind cant fix itself in one kind of object for a longer period of time and only when the intellect becomes pure after spiritual practice then we can try to control it to some extent; only when does continous nigrah (control) of the senses, the mind becomes detached and then after consistent efforts in spiritual practice the mind gets dissolved and it becomes stable and peacefull .