''We say "agni" and think of fire, the word is of no other use to us; to the ancients "agni" means other things besides and only because of one or more of its root meanings was applied to the physical object fire. Our words are carefully limited to one or two senses, theirs were capable of a great number and it was quite easy for them, if they so chose, to use a word like Agni, Varuna or Vayu as a sound-index of a great number of connected and complex ideas, a key-word. It cannot be doubted that the Vedic Rishis did take advantage of this greater potentiality of their language...''
Sri Aurobindo - Early Cultural Writings
Sri Aurobindo explains further the significance of this Vedic hymn to Agni:
अग्निमीळे पुरोहितं यज्ञस्य देवमृत्विजम् ।
होतारं रत्नघातमम् ॥१॥
'Madhuchchhanda Vaisvamitra's Hymn to Agni written in the Gayatri metre in which the first verse runs in the devabhasha,
"Agnim île puro hitam Yajnasya devam ritvijam,
hotaram ratnadhatamam"
and in English,
"Agni I adore, who stands before the Lord, the god who seeth Truth, the warrior, strong disposer of delight."
So the Rigveda begins with an invocation to Agni, with the adoration of the pure, mighty and brilliant God. "Agni (he who excels and is mighty)," cries the Seer, "him I adore." Why Agni before all the other gods? Because it is he that stands before Yajna, the Divine Master of things; because he is the god whose burning eyes can gaze straight at Truth, at the satyam, the vijnanam, which is the Seer's own aim and desire and on which all Veda is based; because he is the warrior who wars down and removes all the crooked attractions of ignorance and limitation (asmajjuhuranam eno) that stand persistently in the way of the Yogin; because as the vehicle of Tapas, the pure divine superconscious energy which flows from the concealed higher hemisphere of existence, (avyaktam, parardha), he more than any develops and arranges Ananda, the divine delight. This is the signification of the verse.
Who is this Yajna and what is this Agni? Yajna, the Master of the Universe, is the universal living Intelligencewho possesses and controls His world; Yajna is God. Agni also is a living intelligence that has gone forth, is srishta, from that Personality to do His work and represent His power; Agni is a god. The material sense sees neither God nor gods, neither Yajna nor Agni; it sees only the elements and the formations of the elements, material appearances and the movements in or of those appearances. It does not see Agni, it sees a fire; it does not see God, it sees the earth green and the sun flaming in heaven and is aware of the wind that blows and the waters that roll. So too it sees the body or appearance of a man, not the man himself; it sees the look or the gesture, but of the thought behind look or gesture it is not aware. Yet the man exists in the body and thought exists in the look or the gesture. So too Agni exists in the fire and God exists in the world. They also live outside of as well as in the fire and outside of as well as in the world.
How do they live in the fire or in the world? As the man lives in his body and as thought lives in the look or the gesture. The body is not the man in himself and the gesture is not the thought in itself; it is only the man in manifestation or the thought in manifestation. So too the fire is not Agni in himself but Agni in manifestation and the world is not God in Himself but God in manifestation. The man is not manifested only by his body, but also and much more perfectly by his work and action, thought is not manifested only by look and gesture, but also and much more perfectly by action and speech. So too, Agni is not manifested only by fire, but also and much more perfectly by all workings in the world,—subtle as well as gross material,—of the principle of heat and brilliance and force; God is not manifested only by this material world, but also and much more perfectly by all movements and harmonies of the action of consciousness supporting and informing material appearances.
What then is Yajna in Himself and what is Agni in himself? Yajna is Being, Awareness and Bliss; He is Sat, with Chit and Ananda, because Chit & Ananda are inevitable in Sat. When in His Being, Awareness and Bliss He conceals guna or quality, He is nirguna Sat, impersonal being with Awareness and Bliss either gathered up in Himself & passive, they nivritta, He also nivritta or working as a detached activity in His impersonal existence, they pravritta, He nivritta. Then He should not be called Yajna, because He is then aware of himself as the Watcher and not as the Lord of activity. But when inHis being, He manifests guna or quality He is saguna Sat, personal being. Even then He may be nivritta, not related to His active awareness and bliss except as a Watcher of their detached activity; but He may also byHis Shakti enter into their activity and possess and inform His universe (pravishya, adhisthita), He pravritta, they pravritta. It is then that He knows Himself as the Lord and is properly called Yajna. Not only is He called Yajna, but all action is called Yajna and Yoga, by which alone the process of any action is possible, is also called Yajna. The material sacrifice of action is only one form of Yajna, which, when man began to grow again material, took first a primary and then a unique importance and for the mass of men stood for all action and all Yajna. But the Lord is the master of all our actions; for Him they are, to Him they are devoted, with or without knowledge (avidhipurvakam) we are always offering our works to their Creator. Every action is therefore an offering to Him and the world is the altar of our lifelong session of sacrifice. In this worldwide karmakanda the mantras of the Veda are the teachers of right action (ritam) and it is therefore that the Veda speaks of Him as Yajna and not by another name.''