Bhagavad Gita Chapter 10, Text 28

Bg 10.28

ayudhanam aham vajram
dhenunam asmi kama-dhuk
prajanas casmi kandarpah
sarpanam asmi vasukih

Word for word: 
ayudhanam — of all weapons; aham — I am; vajram — the thunderbolt; dhenunam — of cows; asmi — I am; kama-dhuk — the surabhi cow; prajanah — the cause for begetting children; ca — and; asmi — I am; kandarpah — Cupid; sarpanam — of serpents; asmi — I am; vasukih — Vasuki.

Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Of weapons I am the thunderbolt; among cows I am the surabhi. Of causes for procreation I am Kandarpa, the god of love, and of serpents I am Vasuki.

Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
The thunderbolt, indeed a mighty weapon, represents Krishna’s power. In Krishnaloka in the spiritual sky there are cows which can be milked at any time, and they give as much milk as one likes. Of course such cows do not exist in this material world, but there is mention of them in Krishnaloka. The Lord keeps many such cows, which are called surabhi. It is stated that the Lord is engaged in herding the surabhi cows. Kandarpa is the sex desire for presenting good sons; therefore Kandarpa is the representative of Krishna. Sometimes sex is engaged in only for sense gratification; such sex does not represent Krishna. But sex for the generation of good children is called Kandarpa and represents Krishna.