The Secret Doctrine of Goddess Lalita
(Sri LalitaAṣṭottara Rahasyārthamu)
53: śāśvatī; 54: śrī śivā
She who is eternal.
She who is the auspicious and divine śiva.
This state of perfection, pūrṇa, is not really a state because it is not transient. It is present at all times - past, present, and future. That which is Self-evident is ever present. Hence, Devī is called śāśvatī, the One that is ever present. Results produced by dharmic deeds, such as the attainment of heaven (svarga), are not permanent. mokṣa is permanent. mokṣa is not absent now. If we say we attained mokṣa now, it implies that we have newly produced or created mokṣa. If we say, we will attain mokṣa in the future, it implies that it is absent now. If it is absent now and must be acquired in the future, there is no comfort because it may be lost in the future. That which can never be negated and is ever present is śāśvatī.
That is the reason why the mṛtyuñjaya mantra does not end with the words mṛtyor mukṣīya. It ends with the another instance of the word mā 'mṛtā́t. This is not meant to be a repetition. A deeper meaning is attached to it. The words mṛtyor mukṣīya expresses the desire to escape death. The word mā 'mṛtā́t expresses the desire to break the cycle of rebirth and attain immortality through liberation. The mantra śāśvatī would have no meaning if one returns to the world after mokṣa. Therefore, mokṣa is not a state like the other states (awake, dream, and deep sleep) that come and go. It is śāśvatī, eternal.
Because Devī is śāśvatī, She is also worshiped as śrī śivā - that which is eternal. That which is born and destroyed is śava (corpse). It is saṃsāra. When we transcend saṃsāra, we attain not just śiva, but śrī śivā. The word śrī denotes śakti/energy and śivā denotes Consciousness. Together they are One. śivaśaktyaikya rūpiṇī is yet another nāma of the divine mother that illustrates the unity or oneness of śiva-śakti, Consciousness-Existence.
If śiva and śakti were not united as One, śiva would be a sava (corpse) without śakti, and śakti would have no existence without śiva. śiva is jñāna śakti (omniscience), and Devī is kriyāśakti (omnipotence). śrī is the power of execution (kriyāśakti). śiva is the Knowledge/Intelligence (jñāna śakti). There is no difference between power (śakti) and the one who wields the power (śiva). This is the basic principle. Therefore, śiva and śakti are One. This Oneness of śiva and śakti has been graphically depicted as ardha nārīśvara in the Siva Purāṇa and other mythologies. We must remember that Consciousness and Its creative power (manifestation) are not two separate entities. Together, they are One. It is this realization that frees us from samsara.