You are air, fire, water, and You are the moon! You are the supreme controller and the grandfather. Thus I offer my respectful obeisances unto You a thousand times, and again and yet again!
The Lord is addressed here as air because the air is the most important representation of all the demigods, being all-pervasive.
Arjuna also addresses
Krsna as the grandfather because He is the father of
Brahma, the first living creature in the universe.