There is Agni (fire), the all-seeing, hidden in the two fire-sticks, well-guarded like a child (in the womb) by the mother, day after day to be adored by men when they awake and bring oblations. This is that.

In plain words: Agni, the fire god who sees everything, hides in the two sticks rubbed together to make fire, guarded like a baby in its mother's womb. People worship it every morning with offerings. This fire is also that Self.