Bg 11.39

vayur yamo ’gnir varunah sasankah
prajapatis tvam prapitamahas ca
namo namas te ’stu sahasra-krtvah
punas ca bhuyo ’pi namo namas te

Word for word: 
vayuh — air; yamah — the controller; agnih — fire; varunah — water; sasa-ankah — the moon; prajapatih — Brahma; tvam — You; prapitamahah — the great-grandfather; ca — also; namah — my respects; namah — again my respects; te — unto You; astu — let there be; sahasra-krtvah — a thousand times; punah ca — and again; bhuyah — again; api — also; namah — offering my respects; namah te — offering my respects unto You.

Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
You are air, and You are the supreme controller! You are fire, You are water, and You are the moon! You are Brahma, the first living creature, and You are the great-grandfather. I therefore offer my respectful obeisances unto You a thousand times, and again and yet again!

Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
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 Krishna as the great-grandfather because He is the father of Brahma, the first living creature in the universe.