The third form is then added, lightning, and therewith Agni is begotten of Indra, and is, therefore, one with Indra: "There is only one fire lighted in many places" (V[=a]l.

10.

2).

As a poetical expression, Agni in the last form is the 'Son of Waters,' an epithet not without significance in philosophical speculation; for water, through all periods, was regarded as the material origin of the universe.
Agni is one with the sun, with lightning (and thunder), and descends into the plants.[4] To man he is house-priest and friend.

It is he that has "grouped men in dwelling-places" (iii.1.