Rig Veda 4.7: HERE by ordainers was this God appointed first Invoker…

HERE by ordainers was this God appointed first Invoker, best at worship, to be praised at rites:
Whom Apnavana, and the Bhrgus caused to shine bright-coloured in the wood, spreading from home to home.

When shall thy glory as a God, Agni, be suddenly shown forth.
For mortal men have held thee fast, adorable in all their homes,

Seeing thee faithful to the Law, most sapient, like the starry heaven,
Illumining with cheerful ray each solemn rite in every house.

Vivasvan's envoy living men have taken as their ensign, swift,
The ruler over all mankind, moving like Bhrgu in each home.

Him the intelligent have they placed duly as Invoking Priest,
Welcome, with sanctifying flame, best worshipper, with sevenfold might;

In his Eternal Mothers, in the wood, concealed and unapproached,
Kept secret though his flames are bright seeking on all sides, quickly found.

That as food spreads forth in this earthly udder, Gods may rejoice them in the home of Order,
Great Agni, served with reverence and oblation, flies ever to the sacrifice, the Faithful.

Bird of each rite, skilled in an envoy's duties, knowing both worlds and that which lies between them,
Thou goest from of old a willing Herald, knowing full well heaven's innermost recesses.

Bright God, thy path is black: light is before thee: thy moving splendour is the chief of wonders.
When she, yet unimpregnate, hath conceived thee, even when newly born thou art an envoy.

Yet newly born, his vigour is apparent when the wind blows upon his fiery splendour,
His sharpened tongue he layeth on the brushwood, and with his teeth e'en solid food consumeth.

When he hath borne off food with swift flame swiftly, strong Agni makes himself a speedy envoy,
Follows the rustling of the wind, consuming, and courser-like, speeds, drives the swift horse onward.