Canto 1 - Boyhood
Bāla-kāṇḍa
Chapter 37: The History of Skanda
Text 1.37.8
इयमाकाशगा गङ्गा यस्यां पुत्रं हुताशनः।
जनयिष्यति देवानां सेनापतिमरिन्दमम्॥
iyam ākāśagā gaṅgā yasyāṁ putraṁ hutāśanaḥ
janayiṣyati devānāṁ senā-patim arindamam
iyam = here is; ākāśagā = flowing through the skies; gaṅgā = Gaṅgā; yasyām = through her; putram = a son; huta-aśanaḥ = Agni; janayiṣyati = will beget; devānām = of the demigods; senā-patim = who will be the commander-in-chief; arindamam = and the destroyer of your force.
Here is Gaṅgā flowing through the skies. Agni will beget the destroyer of the foes, the commander-in-chief of the demigods, through her.
This is the solution.