Kṛṣṇa identified Himself with the vaiśya community because Nanda Mahārāja was protecting many cows and Kṛṣṇa was taking care of them. He enumerated four kinds of business engagements for the vaiśya community, namely agriculture, trade, protection of cows and banking. Although the vaiśyas can take to any of these occupations, the men of Vṛndāvana were engaged primarily in the protection of cows.
Kṛṣṇa further explained to His father, “This cosmic manifestation is going on under the influence of three modes of material nature—goodness, passion and ignorance. These three modes are the causes of creation, maintenance and destruction. The cloud is caused by the action of the mode of passion; therefore it is the mode of passion which causes the rainfall. And after the rainfall, the living entities derive the result—success in agricultural work. What, then, has Indra to do with this affair? Even if you do not please Indra, what can he do? We do not derive any special benefit from Indra. Even if he is there, he pours water on the ocean also, where there is no need of water. So he is pouring water on the ocean or on the land; it does not depend on our worshiping him. As far as we are concerned, we do not need to go to another city or village or foreign country. There are palatial buildings in the cities, but we are satisfied living in this forest of Vṛndāvana. Our specific relationship is with Govardhana Hill and Vṛndāvana forest and nothing more. I therefore request you, My dear father, to begin a sacrifice which will satisfy the local brāhmaṇas and Govardhana Hill, and let us have nothing to do with Indra.”
After hearing this statement by Kṛṣṇa, Nanda Mahārāja replied, “My dear boy, since You are asking, I shall arrange for a separate sacrifice for the local brāhmaṇas and Govardhana Hill. But for the present let me execute this sacrifice known as Indra-yajña.”
But Kṛṣṇa replied, “My dear father, don’t delay. The sacrifice you propose for Govardhana and the local brāhmaṇas will take much time. Better take the arrangement and paraphernalia you have already made for the Indra-yajña and immediately engage them to satisfy Govardhana Hill and the local brāhmaṇas.”
Mahārāja Nanda finally relented. The cowherd men then inquired from Kṛṣṇa how He wanted the yajña performed, and Kṛṣṇa gave them the following directions. “Prepare very nice foods of all descriptions from the grain and ghee collected for the yajña. Prepare rice, dhal, then halavā, pakorā, purī and all kinds of milk preparations, such as sweet rice, rabrī, sweetballs, sandeśa, rasagullā and laḍḍu, and invite the learned brāhmaṇas who can chant the Vedic hymns and offer oblations to the fire. The brāhmaṇas should be given all kinds of grain in charity. Then decorate all the cows and feed them well. After performing this, give money in charity to the brāhmaṇas. As far as the lower animals are concerned, such as the dogs, and the lower grades of people, such as the caṇḍālas, or the fifth class of men, who are considered untouchable, they also may be given sumptuous prasādam. After nice grasses have been given to the cows, the sacrifice known as Govardhana-pūjā may immediately begin. This sacrifice will very much satisfy Me.”
In this statement, Lord Kṛṣṇa practically described the whole economy of the vaiśya community. In all communities in human society—including the brāhmaṇas, kṣatriyas, vaiśyas, śūdras, caṇḍālas, etc.—and in the animal kingdom—including the cows, dogs, goats, etc.—everyone has his part to play. Each is to work in cooperation for the total benefit of all society, which includes not only animate objects but also inanimate objects like hills and land. The vaiśya community is specifically responsible for the economic improvement of the society by producing grain, by giving protection to the cows, by transporting food when needed, and by banking and finance.