1.3. Then the seer dwells in his own nature.
Sutra 1.2 explains the very beginning state of Yoga while Sutra 1.3 states the ultimate goal. To get a better understanding of this, I like to use the word "observer" rather than the word "seer". To be more specific, we can separate these into pure consciousness, which is the observer, and matter, the observed.
The natural state of consciousness is pure observation with no attachment. When a Yogi loosens the bonds of matter from which their consciousness has been trapped in for an untold amount of time, the true nature of the universe is seen. There are many different names for this state of being in other religions. In Yoga and Hinduism, it is called Moksha, or liberation. The Buddhists refer to this is the state of Nirvana and Zen. In Gnosticism, this is the final Gnosis, the ultimate knowledge. Final unity of the one with the whole. In this state, the Yogi has risen above all desires, even the desire to do good. There is no more reincarnation at this level, since there is nothing else to experience. The Ultimate Truth has been revealed.