Yogas citta vritti nirodhah.
Yoga is the control of the mind waves.
Here Patanjali gives us the goal of yoga. When we restrain the mental modifications one has acieved the state of yoga, no longer reacting to what the stories in our head tell or the information our senses pick up. This is the balance that we all seek, to no longer be apart of a mental tug of war between our thoughts. To be at peace with where we are requires this control of the mind waves. Control mean we no longer fall a mental victim to fear, doubt or envy. When our mind is controlled we can read between the lines of our experiences. This control also ignites intelligent action and creation of ideas. With sutra 1:2 we become active creators of our lives.