चतुष्ष्ट्या तन्त्रैः सकलमतिसन्धाय भुवनं
स्थितस्तत्तत्सिद्धिप्रसवपरतन्त्रैः पशुपतिः।
स्वतन्त्रं ते तन्त्रं क्षितितलमवातीतरदिदम्॥

catuṣṣṭyā tantraiḥ sakalamatisandhāya bhuvanaṁ
sthitastattatsiddhiprasavaparatantraiḥ paśupatiḥ |
svatantraṁ te tantraṁ kṣititalamavātītaradidam ||

catuṣṣṭyā tantraiḥ - through sixty four tantra-s; sakalam atisandhāya bhuvanaṁ - betrayed all the worlds; sthitaḥ tat tat siddhi prasava para tantraiḥ - each capable of conferring various psychic powers; paśupatiḥ - Śiva; punaḥ tvan nirbandhāt – subsequently, at Your insistence; akhila puruṣārtha eka ghaṭanā svatantraṁ - capable of conferring all the four human pursuits; te tantraṁ - Your tantra; kṣiti talam – the habitat world (the earth); avātītarat – revealed; idam – this;

“Śiva, by merely revealing sixty four tantra-s that are capable of conferring various psychic powers betrayed the world. But He, due to Your insistence, has subsequently revealed Your tantra, which is capable of conferring all the four human pursuits to the world of humanity.”

Śiva is a Yogic Personality and always remains in meditative mood. He talks only to His Consort, Parāśakti and reveals to Her various methods to attain Him as, in order to attain final liberation, one has to merge with Him. It is only Parāśakti, who reveals Śiva and He cannot be approached directly. The following scene unfolds in Mount Kailaśa (it is only my thought and does not form part of the verse). Śiva is in a relaxed mood and as usual, Parāśakti is sitting close to Him. During this very rare moment, Parāśakti asks a small favour from Him. “O! My Lord! You have revealed sixty four tantra-s to the world that are capable of conferring different superhuman powers. What my devotees are going to do with these siddhi-s? My devotees will never pursue these superhuman powers (it shows Her confidence in Her devotees). They want to attain You and I want to offer them liberation by revealing You to them. Can You kindly do me a favour by revealing a tatnra to my devotees that makes them realize and in turn I will bring them (perfected devotees) up to You for conferring liberation? I will bring before You only the best of my devotees who make themselves fit by practicing the tantra that You may choose to reveal now. I am asking this favour from You for the sake of my devotees. Will You please be kind enough to oblige me, as usual?” Śiva is always pleased with His Consort and agrees to reveal a tantra to attain Her. This is the crux of this verse. It is also equally important to note that liberation can be attained only by worshipping Her. Parāśakti said to Śiva in Mahānirvāṇa Tantra (IV.45), “My Lord! I would like to know the most excellent worship of me leading to unification with You, which You have already described.” Śiva says (IV.9), “Only by worshipping You, individuals can become one with Me.” There is no other evidence required to prove that Śiva can be attained only through the Divine Mother, Parāśakti. Lalitā Sahasranāma 727 is śiva-jñāna-pradāyinī, which means that She alone can impart knowledge of Śiva.

Śiva reveals a Ṣoḍaśī mantra in Mahānirvāṇa Tantra (V.17), which is not known to many. While describing about this mantra Śiva said, “ṣoḍaśīyaṁ samākhyātā sarvatanreṣu gopitā षोडशीयं समाख्याता सर्वतन्रेषु गोपिता” which means “the mantra consisting of sixteen letters will be formed which lies hidden in all the tantra-s and which has been described be me.” This is the mantra revealed by Śiva: hrīṁ śrīṁ krīṁ  parameśvari kālike hrīṁ śrīṁ krīṁ svāhā | ह्रीं श्रीं क्रीं  परमेश्वरि कालिके ह्रीं श्रीं क्रीं स्वाहा।There are many such mantras, though available even today, are nor known and pursued properly. It is also said that by reciting only the first three letters - hrīṁ śrīṁ krīṁ one gets material wealth (Mahānirvāṇa Tantra V.14). The above mantra is capable of giving only the three of the four puruṣārtha-s, where mokṣa is omitted. Śiva is a very clever personality, as after all He is the Supreme Creator. Parāśakti knows that the above mantra or any other mantras revealed by Śiva so far, are not capable of conferring liberation. The one bīja that is capable of conferring mokṣa is parābījā (sauḥ सौः). If we look at any of Śrī Vidyā mantras such as Bālā, Saubhāgya Pañcadaśī and Ṣoḍaśī, they will have parābījā. (sauḥ is made up of three bīja-s and they are “s”, which stands for sat Universal Spirit, “au” which stands for three powers of the Supreme Spirit viz. iccā śakti, jñāna śakti, and kriyā śakti and “ḥ” stands for the Pure Consciousness of Śiva).

Śiva has already revealed sixty four tantra-s (catuṣṣṭyā tantraiḥ) to the world, by way His teachings to Parāśakti. Though the names of all these tantra-s are available, the names of tantra-s vary. It is also believed that total number of original tantra-s were more than sixty four, but only sixty four are available today and the rest were lost with time. These tantra-s, if practiced as revealed in the original Scriptures, are bound to give results much faster. Unfortunately, today there is no proper guidance to teach as per original tantric Scriptures and hence no one derives siddhi-s in the present world.

Worshipping Devi is known as Tantra and the Supreme form of Her worship is Śrī Vidyā, which means auspicious knowledge. It is called auspicious because, all the mantras of Śrī Vidyā confer liberation, provided the procedures are meticulously followed. The basis of Śrī Vidyā is Pañcadaśī Mantra, which is explained in THIS ARTICLE. But Parāśakti pleads with Śiva to reveal a tantra that is capable of conferring all the four puruṣārtha-s – dharma (discharging duty as per precepts of dharma); artha (acquiring material wealth in a proper way); kāma (gratifying desires in the manner prescribed in the above two); and mokṣa (final liberation, emancipation). Hence Śrī Vidyā comes under tantra-s. There are other interpretations about what Śiva has actually revealed to Parāśakti. There are arguments saying that what Śiva had revealed is not Śrī Vidyā tantra but Vāmakeśvara tantra, which also deals with Her worship. The difference between Śrī Vidyā and Vāmakeśvara is where the former takes the worshipper directly to Parāśakti and in the latter, one has to go through mātṛkā devīs and tithi nityā devīs. Therefore, it is always considered that Śrī Vidyā is the best form of worship to attain Her. Worshipping Goddesses is known as Tantra.

Śiva Himself worshipped Her through His own Pañcadaśī Mantra:

ह स क ल ह्रीं। ह स क ह ल ह्रीं। स क ल ह्रीं। ह स क ल ह स क ह ल स क ल ह्रीं ।

ha sa ka la hrīṁ | ha sa ka ha la hrīṁ | sa ka la hrīṁ | ha sa ka la ha sa ka ha la sa ka la hrīṁ  

There is another variation:

क ए ई ल ह्रिं। ह  स क ल ह्रीं। स ह स क ल ह्रीं। क ए ई ल ह स क ह ल स क स क ल ह्रीं ।

ka e ī la hriṁ | ha  sa ka la hrīṁ | sa ha sa ka la hrīṁ | ka e ī la ha sa ka ha la sa ka sa ka la hrīṁ  |

Probably, the purpose of Śiva’s “worship” could have been different, for example, energising Her, transferring His Absolute and Independent Power of Authority (Svātantrya Śakti) to Her, etc. Question is asked by Parāśakti in this verse and the answer is by given in the next verse (32).  When Śiva reveals to Her, Śrī Vidyā Tantra, it overrides all the other sixty four tantra-s as Śrī Vidyā gives emancipation, which other tantra-s do not give that easily. Hence it is often said that Śrī Vidyā is “kevalam mokṣa sādanam” (it is the only way to liberation). However, this verse clearly says that the tantra that is going to be revealed in the next verse confers all the four puruṣārtha-s (caturvidha puruṣārtha siddhyartham).