Sakti Tattva is really the negative aspect of the Siva Tattva. Though they are spoken of separately they are really one. Sakti Tattva is the will of Shiva. Amba, Ambika, Gauri, Gnanambika, Durga, Kali, Rajesvari, Tripurasundari are all other names for Sakti. Sakti is Herself pure, blissful consciousness and is nature itself born of the creative play of Her thought. This Sakti cult is the conception of God as the Universal Mother.
Sakti is spoken of as Mother, because that is the aspect of the Supreme in which She is regarded as the genetrix and nourisher of the universe. But God is neither male nor female. He is named according to the body in which He is manifested.
Hinduism is the only religion in the world which has emphasised much the motherhood of God. The Devi-Sukta appears in the tenth Mandala of the Rig-Veda. It was revealed by Bak, the daughter of Maharshi Ambrin. In this Rigvedic hymn addressed to the Divine Mother, Bak speaks of her realisation of God as Mother who pervades the whole universe. In Bengal, Mother-worship is very prevalent. ‘Ma’ is always on the lips of every Bengali.
Siva and Sakti are essentially one. It is said in the very first verse of Kalidasa’s Raghuvamsa that Sakti and Siva stand to each other in the same relationship as the word and its meaning. Just as heat and fire are inseparable, so Sakti and Siva are inseparable. Lord Siva cannot do anything without Sakti. This is emphasised by Sri Sankaracharya in the first verse of Saundarya Lahari. Read about the Philosophy of Lord Siva Symbols.
Sakti is like the snake with motion. Siva is like the motionless snake. Waveless ocean is Siva. Ocean with waves is Sakti. The transcendental Supreme Being is Siva. The manifested, immanent aspect of the Supreme is Sakti. Siva is attributeless. He is Nishkriya. Sakti is with attributes. She creates. Sakti is compared to a rope made up of tricoloured threads.
Mother Kali dances on the breast of Siva. She has terrible form but She is not really terrible. She is all-merciful and gentle. She wears a garland made up of the skulls. What does this mean? She wears the heads of Her devotees. How loving and affectionate She is to Her devotees!
Kali is the Divine Mother. She is the Sakti or power of Lord Siva. She is the dynamic aspect of Siva. Siva is the static aspect. Lord Siva is like a corpse. What does this signify? He is absolutely calm, motionless, breathless, with His eyes closed in Samadhi. He is actionless, changeless. He is untouched by the cosmic play or Lila that is eternally going on, on His breast. He is absolutely dead to the world. He is beyond the three Gunas.
There is no duality, no plurality, no relativity, no differentiation between subject and object, no distinction, no difference, no Triputi, no Dvandvas, no Raga-Dvesha, no good and evil in Him. He is ever pure, Nirlipta (unattached). And yet He is the source, substratum, support, first cause for this universe. He simply gazes. Sakti is vitalised. She works and creates. In His mere presence Sakti keeps up the play of this universe or Lila. The whole world is a mere vibration or Spandana in Him. He is superconscious and yet He has cosmic consciousness. He constitutes all the names and forms and yet He is above all names and forms. This is a great marvel and a supreme mystery which cannot be comprehended by the finite intellect. Without Siva, Sakti has no existence and without Sakti, Siva has no expression. It is through Sakti that the Impersonal Supreme Being Siva or Nirguna Brahman becomes the Personal Being or Saguna Brahman. Siva or Nirguna Brahman becomes the Personal Being or Saguna Brahman. Siva is the Soul of Durga or Kali. Durga or Kali is identical with Siva. Siva is Satchidananda. Durga or Kali is Satchidananda Mayi. Siva and Sakti are one and neither is higher than the other. Sakti is Chit, Chidrupini, Chinmatra Rupini.
Extract from the book ‘LORD SIVA AND HIS WORSHIP’ By Swami Sivananda.