Episode 21 talks about the 13 yagnas (sacrifituals) BhagavAn has mentioned as part of Jnana Karma Sannyasa Yoga. Out of these 13, the first is post Self realization and the other 12 are pre Self realization. Bhagavan redefines Yagna from a mere fire ritual performed to attain this and other world goodies to selfless actions with brahman as the only image  in mind. This is followed by the four benefits of following his advice and a powerful chapter conclusion stressing the importance of Self knowledge.