‘Agasti’, actually, is not his original name. His original name is ‘Mānya Māndārya’. The name Agasti (Agastya) is derived from ‘Agan Styāyati Iti’ (अगं स्त्यायति इति), which means one who brought to a halt the growth of the Vindhya mountains. He earned his glorious name ‘Agastya’ because of one highly important deed that he performed in his life. According to the Tamil tradition, Agasti is considered to be the disciple of Paramshiva. Narad is considered as the only Devarshi while Agasti is considered as the first Brahmarshi. Therefore, very often, he is referred to as the oldest and the senior most Rishi (Sage). Once, when he was eight years old, he witnessed a bolt of lightning suddenly flash and disappear in an instant. At that moment, he realised that this entire world is transient, momentary, and he set out in search of eternity. At first, he thought the Sun was eternal, so he began praying to the sun. The Sun manifested himself before the young child in a form that he would be able to withstand and explained the reality of his existence. Thus, the young Agasti came to realize that even though the Sun is the guardian of earth, he too is not eternal. What this story conveys is that when Agasti meticulously observed the Sun, its speed and light and contemplated on it, the divine wisdom bestowed upon him, made him aware of the limitations of the Sun in its physical form and the Sun showed him the path to Shiva. In other words, with the help of the science of physics, he found the path to explore the existence of other-worldly things. At that time, he was just sixteen years of age. Despite such a young age, by making use of available resources and by studying with a keen sense of observation, he firmly established the principle of the symbiotic relationship between the existence of the manifest and the unmanifest and it is based on this principle that he lived his entire life. 

The journey of Agasti’s spiritual life towards completeness and perfection was shaped in the following three ways: (a) his disposition and aptitude for studied observation in the nature of penance; (b) his knack and persistence for unravelling the mysteries of the universe; and (c) his awareness of the eternal, infinite and omnipotent power of coordination of the orderly and organized manner of creation and regulation of the universe. During this journey, he became increasingly aware of the auspicious and sacred, ‘Guru' form of Paramashiva. The Paramatma Himself selected him as His first disciple. Paramashiva bestowed Rishi Agasti with the knowledge of all kinds of sciences, arrangement of the sequence of seasons and the eternal truth. Agasti, who had become as radiant as the Sun after acquiring the knowledge from Paramashiva, now respectfully revered the physical form of the sun as the symbol of universal life force. On his return journey, after acquiring the knowledge, considering the sun as his guide, he composed an eloquent and a very beautiful stotra called ‘Adityahridaya’. It is considered to be the first stotra composed by Rishi Agasti. He vowed to recite it 24 times daily at Brahmamuhurta, as a result of which the stotra became so powerful and effective, to deliver even the deities from their predicaments. 

During the war between Ram and Ravana, on the night before the last day of the war, Prabhu  Ramchandra, Lakshman and the entire army were extremely tired; and the next morning, Ravana was expected to resume the battle with more readiness. Rishi Agasti, realizing the gravity of the challenging situation,  visits Prabhu Ramchandra and sitting beside him, they chant the ‘Adityahridaya’ Stotra 108 times. As a result, Prabhu Ramchandra, Laxman and the entire army are completely rid of their fatigue and regain their full strength. Thereafter, Rishi Agasti presents Ram with Indra’s bow and Akshay Bhātā (the quiver having an unending supply of arrows). This meeting has been vividly and extensively described in the Valmiki Ramayana. This support provided by Rishi Agasti himself to Rama, at a very critical moment during the Rama-Ravana war, has always remained unforgettable and venerable for Rama. After his coronation, Prabhu Ramchandra, along with his Panchayatan (five major deities), first performed the Pāḍya Poojan (पाद्य पूजन - ceremonial washing of the feet) of Rishi Agasti with reverence, during which the mantra was recited by his younger brother, Rishi Vasishtha. 

From this story, it is very apparent to the mind about Rishi Agasti’s level of  self-awareness of how the designation ‘Rishi’ stands for upholding social commitment and safeguarding moral values.