Yoga to yoke, to join, to associate, to unite
Ahga components, accessories, aspects
Anusthanat by devoted practice
Kiaye diminish, destroy
Jnana knowledge, wisdom
Diptih shines forth, radiates
Avivekakhyateh the essence of knowledge, the glory of knowledge
By dedicated practice of the various aspects of yoga, impurities are destroyed - the vision of wisdom radiates in glory.
Patanjali summarises the effects of yoga in this one sutra. He says that by habitual and dedicated practice, impurities of the sadhaka's body and mind are consumed, the causes of adversaries removed and the crown of wisdom is acquired. This wisdom and accomplishment keeps the sadhaka guiltless and free of conceit.
Here, instead of the usual word abhyasa (repeated practice), anusthana is used. It is a venerable and noble word with a spiritual significance, implying practice with dedication or religious commitment. The former brings stability; the latter develops maturity of intelligence.
Yoga can cure or diminish one's physical, mental, moral and spiritual woes. Perfection and success are certain only if one practises with love and whole-hearted dedication.