While reading the Sama Veda I came across a hymn to Agni which states something interesting:
Agni, thy faithful servant I call upon thee with many a gift, As in the keeping of the great inciting God.
To Agni, to the Hotar-priest offer your best, your lofty speech, To him ordainer-like who bears the light of songs.
O Agni, thou who art the lord of wealth in kine, thou Son of Strength, Bestow on us, O Jatavedas, high renown
Most skilled in sacrifice, bring the Gods, O Agni, to the pious, man: A joyful Priest, thy splendour drives our foes afar
Taught by seven mothers at his birth was he, for glory of the wise. He, firm and sure, hath set his mind on glorious wealth
Book 2 Chapter 1 Decade 1
Who are these seven mothers referred to in this verse?