The Beast of the mind is a concept that is preliminary. This concept is about the minds lack of boundaries, laziness, stubbornness, volatility, and its lack of training. I call it "the Beast of the mind" because the mind when it is first being cultivated acts like a wild beast that will not allow you full access. Any attempt to corral it will bring up spasms of violence, futility, and inconvenience. "Restlessness is a loss of self-mastery." The beast is restlessness and the goal is self-mastery. Whenever we find ourselves restless, this is the beast beckoning and rearing. Keep your thoughts on self-mastery, realize the restless beast will not allow you to ride with out vigilance and determination. Keep adamant, keep yourself content, and disallow restlessness. Always know you are in "the right place, at the right time, with the right reason, and the right intention."
Elementary learning is Identification of restlessness
Advanced learning is the renunciation of restlessness