Tatparam that highest, that most excellent, the ultimate, the best, the purest, the supreme
purusakhyateh the highest knowledge of the soul, perception of the soul
gunavaitrsnyamindifference to the qualities of nature, inertia or dormancy (tamas), passion or vibrance (rajas) and luminosity or serenity (sattva)
The ultimate renunciation is when one transcends the qualities of nature and perceives the soul.
If through abhyasa one can activate and purify one's energy, through vairagya one can disinvolve oneself from involvement in even the subtlest manifestations of the phenomenal world. The creation of energy alone, without control or restraint, cannot lead to freedom. Here, one sees the unfolding of nature from its noumenal (alihga) state into the lihga state, through mahat; then from the non-specific (aviiesa) phenomena, including ahamkara, ego or 'I-consciousness' to the manifest (visesa) expressions of nature, which forms the foundation of one's experience of everyday reality. The reverse or involutionary process, which is the path of yoga, can be seen as the ascension of a ladder. Abhyasa furnishes one the necessary impulse for the rise; by vairagya one draws up the ladder behind them.
The lower rungs of renunciation are attempted by anyone who tries to disengage himself from such a habit like smoking or drinking coffee. One generally tries to cut down, then to stop, but the desire lingers on in the mind. When that mental desire has faded away, years later, the body cells may spontaneously rekindle attachment. Later still, one might find that one has become attached to the idea of oneself as non-drinker of coffee; therefore the ego is still attached to the idea of coffee even though it is now 'non-coffee'. This is self-conscious virtue. Slowly one might become entirely unresponsive towards coffee, but coffee whatsoever still subsists in the mind.
This sutra relates to the ultimate freedom achieved through paravairagya - here phenomenal nature ceases to exist, as the gunas are transcended, drawn back into their noumenal root. By transcending the gunas, one unlocks that which binds one to nature. When this is achieved in all the involvements, the soul is fully perceived.
The consciousness has now, by the power of wisdom, gained everything that had to be acquired, and tossed away everything that had to be discarded. The sadhaka is liberated from all bondage; there is no feeling of birth and death. Kaivalya is accomplished. This is the effect of the twin disciplines of abhyasa and vairagya, through which the sadhaka turns wise and free, untarnished by the influence of citta.
In iv.29 the word prasahkhyana, meaning 'highest knowledge', has been used. Again in sutra iv.31, there is the expression sarvavarana malapetasya which means 'when all obscuring impurities are destroyed totally'. Then succeeds purusakhyati, standing for 'perception of the soul'.