The ancient Yoga Sutras tell us that yoga is "citta vrtti nirodhah."
The word citta is commonly translated as mind or consciousness;
the word vrtti (literally, "whirlpool") means to spin or fluctuate restlessly;
and nirodhah means to restrain, tame, or subdue.
Thus the practice of yoga is the taming of the restless mind.
This restlessness is the obstacle that prevents us from realizing our own true nature, and keeps us from finding peace and harmony in our lives.
The ancients understood the difficulty of taming the mind, comparing it to trying to harness the wind.
We know from our own lives that the mind is fickle, rebellious, strong, and stubborn, refusing any attempt to control it.
However we can, through consistent, dedicated practice, begin to align the body, and bring it to a state of harmony.
We practice asana (postures), starting with the extremities (feet, hands, legs, arms, hips, shoulders).
We work our way gradually inwards (spine, inner organs, breath, nerves, senses).
In this way, subtly, over time, we bring a sense of steadiness and calm to both body and mind.
In the Yoga Sutras it is written that when the restlessness of the mind is subdued, the Self may abide in its own true nature.