Excerpt from the book ADHYATMIKTA
Legend, as mentioned in yāmala texts like Rudra and Brahma, attests to a story, with slight variations, wherein Vasistha, son of Brahma, practiced severe austerity in Blue Mountains, Nilachala, at the site of the celebrated temple of goddess Kāmākhyā.
Unable to succeed in his sādhanā in spite of strenuous effort, an angry Vasistha asks Brahma for a different mantra, or he would curse this Mahāvidyāḥ. Brahma stops him from uttering the curse and then describes Tārā as a Supreme Shakti who saves from all dangers, as lustrous as ten million suns, as soothing as ten million moons, dark blue (Nila) in color, with a brilliance surpassing ten million lightning flashes.
He further says that in Her there is neither dharma, nor adharma, present in the form of all, She is attached to Shuddhacinācārarata (pure Cinācarā) as an embodiment of intelligence, buddhiswari, buddhirupa, and originating from the Atharvaveda, atharvavedasakhini.
On receiving this new advice, Vasistha then spends another 1000 years in austerities with the new mantra and yet does not succeed. Now doubly determined to curse this Mahāvidyāḥ, for he is certain that this does not work, he does acamana by sipping water, when suddenly he hears the Devī Herself telling him that Her path is different from the Vaidika method he is pursuing. He must immediately go to mahācīna, where a Buddharupi Narayana will instruct him in the appropriate manner of upāsanā which brings quick success.
On reaching mahācīna Vasistha became further agitated, so goes the story, when he sees a Buddha (not the historical Śākyamuni) indulging in the Pañcatattva rites which to his unaccustomed eyes looked nothing less than perversion and outside of the Vedic acara.
It is then that the said Buddha transforms into Narayana and the three intoxicated women surrounding him transform into the three MahāShaktis, and he enters into a colloquy with a thoroughly disturbed Vasistha, wherein he explains to the latter the real significance of these rituals and the glory of the Kulamārga, which, according to the Buddha was beyond the ordinary Vaidika ritual, Vedanamapyagocarah.
While this may come as a bit of a surprise to those who are uninitiated into Tantric literature, this kind of argument is neither new nor rare. In fact, that there was a serious difference of opinion in certain class of Tantras with the Vaidika ritualism becomes clear when we find that Vedacara was considered to be the lowest, or rather the most basic kind of acara in the progression of upāsanā fit for laymen, while kaulacara was the final sign of spiritual supremacy.
Philosophically, however, there is quite a bit of similarity between the description of various spiritual states in the Upanishadic literature and Tantric literature. It is in the ritual corpus that Tantra, especially the left-hand variety, marked out an independent path from the Vaidika traditions.
The idea was that the seeker must develop detachment even in those circumstances and activities which are otherwise considered impure and polluted, for one who is in the highest state of consciousness, everything appears to be filled with the essence of the Divine Shakti just as the ancient Greeks had profoundly observed, “panta kathara tois katharois” – to the pure, all things are pure.
The goddess, into whose worship Rishi Vasistha was initiated became known formally as Mahachina Tārā and eventually metamorphosed into Tārā, who is accorded the high status of a Mahavidyāḥ in the Hindu Tantric pantheon.