Translation Now, the chapter on Samadhi Now, the instruction of Yoga
Interpretation The Yoga Sutras are divided into 4 chapters (Padas), in this particular order: Chapter 1—chapter on Samadhi being enstasy or spiritual/mystical absorption Chapter 2—chapter on Sadhana being spiritual practice Chapter 3—chapter on Vibhuti or powers Chapter 4—chapter on Kaivalya being the state of unconditional existence of the Self, which is true Freedom (from the body, mind, conditions and the world).
This demonstrates not only a logical sequence but also alerts the mind of the sincere seeker, the Sadhak, as to what to expect when travelling the Yoga path.
The aim of Yoga is unconditional Inner Freedom by experiencing the Self Within as our immortal, eternal True Nature. This is chapter 4 (the apogee of the path). In order to become Self-Realized one first needs to experience Samadhi (mystical absorption into the Self), so this is chapter 1; how we can get there is through dedicated Sadhana, or spiritual practice, this is chapter 2. As we learn to focus the mind, the mind not only conserves a lot of energy but increases its efficiency through its expanded abilities to concentrate. This is when the Sadhak starts developing powers or Siddhis. Patanjali warns us not to get distracted by those powers lest we become megalomaniacs and abuse and misuse them. This is chapter 3. Getting lost in the Siddhis or powers of the mind is a recipe for disaster and forgetting the true aim of Yoga which is Inner Freedom, liberation from all fetters of the mind (chapter 4 of the Sutras).
So going back to verse I.1, Patanjali directs our mind to what this initial chapter is about: Samadhi or mystical absorption leading to the state of enstasy or Inner Bliss which is a pure Self-implosion, a Satori, an insight into our Enlightened Nature versus ecstasy which at best is a rapturous delight experienced by the mind and therefore still within the realm of the temporal. Next, Patanjali directs our mind to the instruction of Yoga, basically Yoga and its aims.
If we look at the root of words to extract their intended meanings then we will also obtain their intended purpose (i.e. inherent aim). The word Yoga comes from the Sanskrit root, Yuj meaning “to yoke, harness” and “union”, signifying a merging. The union implied here as we will see through unravelling the Sutras is a mystical one, of the stripped little self with the God-Self, of the wave with the ocean where the ocean has become the wave (the ocean being Consciousness itself), the Atma (the Self) becoming indistinct from Brahman (the Absolute, the One Without a Second).
This is why in the Eastern Teachings, a Fully Self-Realized Guru is considered to be no different to the Absolute. One must of course remember that the Guru is the Spirit Within and not the body or personality in which that Spirit temporarily resides as its abode of expression. The real Guru is one who makes the disciple realize the Self Within (and not one who builds empires or formulates a sect of adoring fans).