The demigods are empowered administrators of material affairs. The supply of air, light, water and all other benedictions for maintaining the body and soul of every living entity are entrusted to the demigods, who are innumerable assistants in different parts of the body of the Supreme Personality of Godhead. Their pleasures and displeasures are dependent on the performance of yajnas by the human being. Some of the yajnas are meant to satisfy particular demigods; but even in so doing, Lord Visnu is worshiped in all yajnas as the chief beneficiary. It is stated also in the Bhagavad-gita that Krishna Himself is the beneficiary of all kinds of yajnas: bhoktaram yajna-tapasam. Therefore, ultimate satisfaction of the yajna-pati is the chief purpose of all yajnas. When these yajnas are perfectly performed, naturally the demigods in charge of the different departments of supply are pleased, and there is no scarcity in the supply of natural products.
Performance of yajnas has many side benefits, ultimately leading to liberation from the material bondage. By performance of yajnas, all activities become purified, as it is stated in the Vedas:
ahara-suddhau sattva-suddhih sattva-suddhau
dhruva smrtih smrti-lambhe sarvagranthinam vipramoksah
As it will be explained in the following verse, by performance of yajna one's eatables become sanctified, and by eating sanctified foodstuffs, one's very existence becomes purified; by the purification of existence, finer tissues in the memory become sanctified, and when memory is sanctified, one can think of the path of liberation, and all these combined together lead to Krishna consciousness, the great necessity of present-day society.