Tripadādyanuprāṇanam त्रिपदाद्यनुप्राणनम्॥ (sūtra III.38)
tripada – manifestation, maintenance and reabsorption of each of those states; ādi – the principal achievement; anuprāṇanam – invigorating
The three lower levels of consciousness viz. awake, dream and deep sleep states invigorates into the fourth state of consciousness viz. turya, where the creative principal unfolds. Turya is the state where bliss blossoms forth. When this blossomed bliss is passed into the three lower level of consciousness, all the states of consciousness become a unified state of consciousness. This is how a yogi continues to exist, eternally connected to the Lord. He is able to distinguish between what is real and what is not real. He knows well that his body is perishable and therefore, he chooses not to attach any importance to his gross body. On the other hand, he also knows that Reality means the highest level of consciousness. This is the stage where the mind is devoid of any other thoughts except the Self-illuminating Lord. He understands that what is Self-illuminating is the Supreme and all the rest that shines with the aid of that Effulgence are susceptible to extinction at some point of time.
Śiva alone is Self-radiating and hence, He is the foundational cause of all the creations. He does not directly partake in the process of creation. Out of His unobstructed will power, He creates Śaktī and transfers His exclusive power of autonomy to Her by means of a power of attorney to effectively administer the universe by three acts viz. creation, sustenance and absorption of souls. This is the difference between advaita and trika philosophies. Advaita speaks only about dyads, the Lord and the soul. But Trika philosophy talks about triad, puruṣa, which is known as soul in advaita philosophy, Śaktī, an additional player, exclusive to Trika philosophy and finally the Lord or the Brahman, which in this case is Śiva. Therefore, as far as Trika philosophy is concerned, Śiva is the ultimate and Śaktī is merely His power of attorney holder for effective administration of the universe. When a nara (manifested soul) ultimately attains liberation, it means He merges with Śiva, and the cause of liberation being Śaktī. In Advaita philosophy, the merger of the soul happens with the Brahman. Brahman is the form given to one’s Iṣṭa devata. There is no intermediary between the practitioner and his Iṣṭa devata. This recap becomes necessary, as we are heading towards the end of Śiva Sūtra-s. The difference though appears to be significant in reality the difference is extremely subtle, but as powerful as a thin razor edge.
One enters the state of bliss, out of the grace of Śaktī alone. She assumes a twin role for the upliftment of the aspirant. Primarily, She becomes their compassionate Mother (this aspect is discussed more elaborately in advaita scriptures like Lalitā-Saharasranāma) and also their spiritual master as She alone decides eligibility criteria of the aspirant to ultimately merge with Her consort Śiva. Śaktī not only becomes the subject of bliss, but also becomes the object of bliss. Apparently, to realise inherent happiness, one has to look within. A mind that is totally purified and becomes devoid of thought process alone becomes eligible to enter the state of blissfulness or ānanda.
This aphorism says that the blissfulness state should be imbibed in other three mundane level of consciousness, so that one continues to remain in turya state, transcending all the karmic afflictions. His spiritual journey has not concluded yet, as he still realises the effulgence of the Lord intermittently and not perpetually.
Sūtra III.20 almost conveyed the same interpretation. But there is a subtle difference between the two. Sūtra III.20 said that turya state should be poured into the lower states of consciousness continuously and the present sūtra says that the aspirant continues with his routine by invigorating turya state into the lower states of existence.