So many methods have been suggested for self-improvement, such as suppression of evil habits, substitution or sublimation, positive thinking, prayer, penance, living in tune with the infinite or God. Surely all these have their usefulness in this world. However, we often forget that there has to be intense sincerity if they are to be useful. Such sincerity invariably brings us face to face with our own mind and its mischievous ways. And that is yoga.
If these methods are applied mechanically, we might only be turning away from our mind and, under the veneer of holiness, there may flourish terrible ugliness, which will assert itself during unguarded moments. One who is intensely sincere and ever watchful of his mind is truly virtuous, because he sees directly the self-destructiveness of the opposite of what the Yoga Sutras describe as virtues or yamas.
It may be said that he is constantly in tune with God – therefore a bhakta, and his unselfishness flows from him as loving service to all – therefore he is a karma yogi, and he knows himself through and through – and therefore he is a Jnani.