Practice & the First Chapter of the Yoga Sutras
The first chapter of Patanjali's Yoga Sutras is called "Samadhi Pada. It explains the significance of yoga and provides guidance in the disciplines of practice and detachment in order to help aspirants to reach the vision of the soul. Samadhi also refers to cognitive absorption, the ability to remain aware and mentally where you are at - basically to focus.
In our pure self and consciousness we are (each one of us) perfect and pristine. However, our minds like to self-criticize and thereby build up obstructions to seeing (being awareness) of our perfection and this leads to suffering.
The good news is that the practice of yoga slowly clears up those obstructions of awareness, leading the mind to a more perceptive and reflective state.
By practicing non-attachment (through yoga) one can stop the fluctuations of the mind (that wild monkey in your head), this is called Nirodha in Sanskrit. Non-attachment essentially is the removal of coloring in our perception and it is most efficient when it transcends the qualities of the gunas (creation (sattva), preservation (rajas), and destruction (tamas)).
A person who practices intensely is closer to nirodha (ceasing the fluctuations of the mind), see Sutra 1.14 "Practice for a long time, without interruption, with consistency and enthusiasm is the firm foundation for restraining the fluctuations of the mind". Importantly, the ceasing of the fluctuations of the mind start directly in the asana practice when ceasing movements in the asana itself (stillness in the pose) and turning and asana into a seal of awareness.
Faith in the practice, energy, memory (discipline is purifying memory), insight and samadhi (focus) help to attain nirodha.