2.27 Steady wisdom manifests in seven stages.
2.28 On the destruction of impurity by the sustained practice of the limbs of Union, the light of knowledge reveals the faculty of discrimination. 2.29 The eight limbs of Union are self-restraint in actions, fixed observance, posture, regulation of energy, mind-control in sense engagements, concentration, meditation, and realization.
I don't understand why these passages are not in the first chapter of the Yoga Sutras. They are fundamental to the practice and set the tone for the rest of book two. Up until this point, most of the Sutras have been about theory and philosophy. Now we are getting into practice. So, lets start by going over the eight limbs of Yoga, shall we?
Squidward should have eight limbs, but has six. I don't care. I love Squidward.
Self-restraint in action is referred to as the Yamas. They are Nonviolence, sexual abstinence, not lying, not stealing and greed. They are the "Do Nots" of Yoga. The fixed observances, or virtues, are called Niyamas. They are: purity, contentment, austerity, self-reflection and contemplation on God. The Yamas and Niyamas go hand in hand. I will go into more detail about this later in the book. Each one is covered in a separate sutra.
You may have heard the term Asana if you have taken a Hatha Yoga class. Asana simply mean posture. In this context, we are talking about the proper posture for meditation.
Regulation of energy, also known as Pranayama, or breath control, is intimately linked with our life-force. Focusing on the breath is used to bring our attention to something unconsciously regulated into awareness. Energy flows into the body via oxygen when we take an inhalation and exits the body during exhalation. When the oxygen levels are perfectly balanced in the body, the Yogi can reach the breathless state, bringing them to the height of meditation.
Mind control in the sense engagements means that one tries to master the interactions with the outside world in the mind through senses. The senses are like roadways with traffic flowing in each direction. We take in information, process it, and react accordingly. Mastery over the flow of information gives us freedom to choose our actions with detachment.
The final three, meditation, concentration and realization work in unison. Concentration is the act of focusing on an object while deliberately ignoring other streams of thought. Meditation has a lot of connotations, but in Yoga, it basically is a letting go of the grip that symbolism has on the mind. Realization is the combination of meditation and concentration, which seems like a contradiction. It is in a way, because it is something we have to experience for ourselves.
It’s going to take some time to work through the second half of book two.
There is a lot of good stuff here and I want to do my best to explain it.
I hope you will enjoy it as much as I do.