Yoga is an art and a science as well as a philosophy. Yoga touches the life of man at all levels, whether it is physical, mental or spiritual. Yoga is a practical method for making one's living purposeful, useful and noble. Yoga enables one's body, organs of actions, senses of perception, mind, intelligence, consciousness as well as trillions of cells to get attuned to its essence – the conscious seer within. Yoga alone enables the seer to directly perceive and experience using his vestments for the world within and around himself to gain insight and feel the divine joy of all creation. The Yogi then shares the Amrita, the nectar of divine wealth and happiness with his fellow beings.
Uninterrupted practice of Yoga done with devotion keeps the practitioner free from motivation, desire for reward, and he develops discriminative intelligence. This discriminative intelligence which develops in the practitioner of Yoga keeps his mind free from contact of the tempting objects and yokes it to the soul which is unmoving, unrotating but ever in the state of present.
Through reverential practice of Yoga, the fire which emanates from the practice burns out the impurities of body, mind and intelligence and bestows the consciousness with the crown of wisdom for it rests on the lap of the Self. From then on the never changing intuitive light of the Self radiates and frees the practitioner from the actions which are filled with afflictions.
Sutra, which is usually translated in English as "an aphorism", literally means "a thread". Like a thread in a rosary (Mala) threads all the beads and prevents them from falling apart, in the same way these Sutras act as a thread that is threading all the beautiful divine truths and concepts that are called Yoga collectively and prevents them from falling apart. So the Yoga Sutras of Patanjali are like a rosary (Mala) in which the beads are the divine truths.
Darshanam, which is usually translated in English as "philosophy" (i.e. love for wisdom), literally means "a vision, a realization". This indicates that the truths that have been described in the classical text of the Yoga Sutras are not just existing in theory, they are not just a hypothesis, but they have been "seen" by those great Seers, they have been realized by them. They had integrated those truths in their own lives.
These disciplines channel the energies of the organs of action as well as the perceptive senses in the right direction. It is essential that they be observed and followed. Without firm foundation a house cannot stand. Withoutthe practice of the principles of Yama and Niyama, which lay the firm foundation for building character, there cannot be an integrated personality. Practice of Asanas without Yama and Niyama is mere acrobatics.
Discipline does not arise from one's own mind. It has to be learned from outside. External discipline puts you on the right path. Only a disciplined persone is a free person. Patanjali says the rules of Yama and Niyama are the mighty universal vows. They are the golden keys to unlock the spiritual gates.