What is the path to liberation as outlined in Chapter 19, and what is considered the primary obstacle?

The path to liberation, as detailed in Chapter 19, is a sequential process. It begins when the mind perceives the world as transient, which is necessary for the idea of detachment to spark. This detachment is crucial because, as the chapter states, knowledge is not attained without it, and there is no liberation without knowledge. The primary obstacle is the ego's identification with the body, intellect, and mind. As long as this sense of being a 'doer' and 'enjoyer' remains, the experience of pleasure and pain is unavoidable, preventing one from attaining the Supreme Self, which is the ultimate fulfillment and duty of human birth.