The Yoga Sutras are divided into four chapters (or padas), each one focusing on a different aspect of the yogic practice. The first pada (Samadhi Pada) concentrates on the ultimate goal of yoga, known as samadhi. Samadhi is a blissful state of total meditative absorption and can only be attained through dedicated practice. In this first pada, Patanjali acknowledges the many different obstacles a sadhaka (practitioner) encounters along their sadhana (spiritual path) leading to samadhi. One might wonder why Patanjali began his writings with the final (and thus most advanced) state of the yoga practice. Iyengar believes that ‘the enticing prospect of samadhi, revealed so early in his work, serves as a lamp to draw us into yogic discipline’.
In the second pada (Sadhana Pada), Patanjali outlays the fundamentals of an eight-staged practice designed to attain the aforementioned samadhi. Known as astanga yoga, this eight-limbed practice is as familiar to us yogis as the Bible is to Christians. I won’t open a can of worms, but I will note that one of these limbs, asana, has become an enormously popular physical exercise in Western society, and is what most people think about when they hear the term ‘yoga’.
In the third pada (Vibhuti Pada), Patanjali whispers of extraordinary powers a yogi can potentially earn through a dedicated practice of astanga yoga (some of these special skills include the reading of minds and walking on water). Patanjali warns the reader, however, that a sadhaka can become enamored by these special abilities and stray from their sadhana, thus inducing ego. He further states that a perfect yogi will refuse to exercise his powers and maintain a steady focus on their sadhana.
The fourth and final pada (Kaivalya Pada) expounds upon the sadhaka’s soul once he has reached the state of samadhi. Samadhi Pada describes yoga’s final state, but it doesn’t exactly describe the personality of an enlightened yogi. What does a yogi do once he has attained samadhi? Kaivalya Pada explains just that. In a sense, it is a manual for ultimate spiritual living.
Excerpt from goodyoga.com blog post Light on the Yoga Sutras of Patanjali by BKS Iyengar