Trishul is one of the most powerful weapons mentioned in Hindu texts and epics and is wielded by Lord Shiva.
Lord Shiva's Trishul-Astra, or trident, has come to be associated with numerous triad attributes.
1. Shiva’s Trishul represents the three fundamental aspects of life. These are the three basic Nadis – (Ida, Pingala and Shushmana).
2. The Pingala and Ida represent the basic duality in the existence. Shushmana, the central one, continues upward to the 7th chakra, (There are 7 chakras in human body) or energy centre, while the other two end at the brow, there the 6th chakra is located. The Trishul's central point represents Shushmana, and that is why it is longer than the other two, representing Ida and Pingala.
3. The three prongs of Trishul represents:
Three Devs: Brahma, Vishnu , Mahesh.
Three Devis: Sarasvati, Lakshami and kaali.
Three Shaktis of Shiva: Iccha (will), Gyana (knowledge) and Kriya (action).
Three aspects of Shiva: Paramashiva, Parashakti (Paranada or Shiva-Tattva) and Parabindu (Parameshvara or Shakti-Tattva).
Three modes of nature: creation, maintenance and destruction.
Three Kaal: Bhoot (Past), Vartaman (Present) and Bhavishya (Future).
Three Gunas: Sat , Raj , Tam
Three Lokas : Swarg , Bhu and Patal.
Three Powers: Will, Action and Wisdom.
Three types of miseries: Physical, Mental and Spiritual.
4. Shiva held Kashi city during Pralaya over the tip of his trishul.
ब्रह्मणश्च दिने सा हि न विनश्यति निश्चितम्।
तदा शिवस्त्रिशूलेन दधाति मुनयश्च ताम्।। २३ ।।
Even after the completion of a divine day of Brahmā, the city of Kashi does not get destroyed. O Sages, at that point of time, Shankar holds it over the tip of his trident.
Both Kashi and Trishul got dissolved during Mahapralaya.
5. Functioning as the primary weapon of Shiva the Destroyer, Trishul is said to be capable of destroying the three worlds.
6. The Damaru in his left hand represents the Sabda Brahman, It represents OM from which all languages are formed.
7. Trishul is polyvalent and rich. It has the capacity to remove different negative qualities which inhibit us to be one with the almighty.
8. In Lord Shiva's homelands, the great Himalayas, there is a place in Nepal called Gosaikunda Lake (or Gosain-kunda), which is said to have been formed by Shiva's trishul. This took place as part of his pastime of drinking the poison ocean, or Halahal from Samudra-Manthan (churning of the ocean). After drinking the poison, Shiva craved cold water to quench the overwhelming heat, and he came to the alpine freshwaters at Gosaikunda to get relief.
9. The Trishul was also the symbol of Navnatha, who are religious leaders, or gurus, or guides, who derive their names from Adinatha, or Shiva. Shiva himself is called a Natha.
शिवम् करोति इति शिव:
(Shivam Karoti Iti Shivaha)