1.12 abhyasa-viragyabhyam tan-nirodhah
Practice and detachment are the means to still the movements of consciousness. (BKS Iyengar)
Here patanjali announces the path to stilling consciousness. It is through this two-fold path that the yogi can reach the goal of yoga.
BKS Iyengar, in his commentary, beautifully compares practice and dispassion as opposites. Sun and Moon (Ha and Ta), positive (practice) and negative (dispassion). And, as he states, they must be paired or the yogi is out of balance. Practice is a building or adding, and in a way, dispassion is a subtracting.
For me this is easy to see. In my experience, the practice is the easier part (while still challenging). For example, this month I have been working on practicing metta all day long; practicing my asana and pranayama; meditating, etc. But pushing away the sensual (which is really at the heart of dispassion) is much more difficult. I am hugely influenced by food (even when not hungry), I am attracted to external stimuli (anything glittery and shiny pulls me in - whether literally or figuratively), and the list goes on. It is my job, then, to pull myself into balance. I cannot spend money using just one half of the coin - it has to be the coin in its entirety.
In his commentary, Edwin Bryant brings up the idea of a person either moving toward liberation or away from liberation. And that path is determined by whether the individual is following this path or not. I have heard other yogis (Swami Tiogonanda comes to mind) who say that we are all moving in the direction of liberation, but our work either speeds up the process or keeps us moving at the regular slow sluggish pace. I like to believe that the latter is true. That we will get there eventually, but we can do our best to do what is right and be unperturbed by the realm of sensual desires.