"The Lord created this material world for the conditioned souls to learn how to perform yajñas (sacrifice) for the satisfaction of Viṣṇu, so that while in the material world they can live very comfortably without anxiety. Then after finishing the present material body, they can enter into the kingdom of God. That is the whole program for the conditioned soul. By performance of yajña, the conditioned souls gradually become Kṛṣṇa conscious and become godly in all respects. In this age of Kali, the saṅkīrtana-yajña (the chanting of the names of God) is recommended by the Vedic scriptures, and this transcendental system was introduced by Lord Caitanya for the deliverance of all men in this age. Saṅkīrtana-yajña and Kṛṣṇa consciousness go well together. Lord Kṛṣṇa in His devotional form (as Lord Caitanya) is mentioned in the Śrīmad-Bhāgavatam as follows, with special reference to the saṅkīrtana-yajña:
yajanti hi su-medhasaḥ
'In this age of Kali, people who are endowed with sufficient intelligence will worship the Lord, who is accompanied by His associates, by performance of saṅkīrtana-yajña.' (SB 11.5.32) Other yajñas prescribed in the Vedic literatures are not easy to perform in this age of Kali, but the saṅkīrtana-yajña is easy and sublime for all purposes."
(Bhagavad-gītā As It Is 3.10, Purport)
"No one can manufacture anything. Take, for example, all the eatables of human society. These eatables include grains, fruits, vegetables, milk, sugar, etc., for the persons in the mode of goodness, and also eatables for the nonvegetarians, like meats, etc., none of which can be manufactured by men. Then again, take for example heat, light, water, air, etc., which are also necessities of life—none of them can be manufactured by the human society. Without the Supreme Lord, there can be no profuse sunlight, moonlight, rainfall, breeze, etc., without which no one can live. Obviously, our life is dependant on supplies from the Lord. Even for our manufacturing enterprises, we require so many raw materials like metal, sulphur, mercury, manganese, and so many essentials—all of which are supplied by the agents of the Lord, with the purpose that we should make proper use of them to keep ourselves fit and healthy for the purpose of self-realization, leading to the ultimate goal of life, namely, liberation from the material struggle for existence. This aim of life is attained by performance of yajñas. If we forget the purpose of human life and simply take supplies from the agents of the Lord for sense gratification and become more and more entangled in material existence, which is not the purpose of creation, certainly we become thieves, and therefore we are punished by the laws of material nature. A society of thieves can never be happy because they have no aim in life. The gross materialist thieves have no ultimate goal of life. They are simply directed to sense gratification; nor do they have knowledge of how to perform yajñas. Lord Caitanya, however, inaugurated the easiest performance of yajña, namely the saṅkīrtana-yajña, which can be performed by anyone in the world who accepts the principles of Kṛṣṇa consciousness."
(Bhagavad-gītā As It Is 3.12, Purport)
"The performance of yajña is a very difficult task because all the demigods must be invited to participate in the yajña. In this Kali-yuga it is not possible to perform such costly sacrifices, nor is it possible to invite the demigods to participate. Therefore in this age it is recommended, yajñaiḥ saṅkīrtana-prāyair yajanti hi sumedhasaḥ (SB 11.5.32). Those who are intelligent should know that in the Kali-yuga there is no possibility of performing the Vedic sacrifices. But unless one pleases the demigods, there will be no regulated seasonal activities or rainfall. Everything is controlled by the demigods. Under the circumstances, in this age, in order to keep the balance of social peace and prosperity, all intelligent men should execute the performance of saṅkīrtana-yajña by chanting the holy names Hare Kṛṣṇa, Hare Kṛṣṇa, Kṛṣṇa Kṛṣṇa, Hare Hare/ Hare Rāma, Hare Rāma, Rāma Rāma, Hare Hare. One should invite people, chant Hare Kṛṣṇa, and then distribute prasāda. This yajña will satisfy all the demigods, and thus there will be peace and prosperity in the world. Another difficulty in performing the Vedic rituals is that if one fails to satisfy even one demigod out of the many hundreds of thousands of demigods, just as Dakṣa failed to satisfy Lord Śiva, there will be disaster. But in this age the performance of sacrifice has been simplified. One can chant Hare Kṛṣṇa, and by pleasing Kṛṣṇa one can satisfy all the demigods automatically."
(Śrīmad-Bhāgavatam 4.6.53, Purport)
"As soon as the process of yajña is stopped, the earth will withhold all productions—vegetables, trees, plants, fruits, flowers, other agricultural products and minerals. As confirmed in Bhagavad-gītā, the process of yajña was instituted from the beginning of creation. By the regular performance of yajña, the equal distribution of wealth and the restriction of sense gratification, the entire world will be made peaceful and prosperous. As already mentioned, in this age of Kali the simple performance of saṅkīrtana-yajña—the holding of festivals as initiated by the International Society for Krishna Consciousness—should be introduced in every town and village. Intelligent men should encourage the performance of saṅkīrtana-yajña by their personal behavior. This means that they should follow the process of austerity by restricting themselves from illicit sex life, meat-eating, gambling and intoxication. If the intelligent men, or the brāhmaṇas of society, would follow the rules and regulations, certainly the entire face of this present world, which is in such chaotic condition, would change, and people would be happy and prosperous."
(Śrīmad-Bhāgavatam 4.18.13, Purport)
"So yajña is yajñārthe karmaṇo 'nyatra. Everything should be done for the Yajña, for Viṣṇu. Then everything is in order. In Kali-yuga, other, costly yajñas are not possible. Therefore yajñaiḥ saṅkīrtana-prāyaiḥ. Saṅkīrtana. But these rascals will not take. If you say that 'This simple yajña, you take it. Chant Hare Kṛṣṇa mantra. All problems will be solved,' they will not believe it. They will not take it. They are so misfortunate. Śāstra says, yajñaiḥ saṅkīrtana-prāyair yajanti hi su-medhasaḥ. Su-medhasaḥ, therefore, those who have got good brain, they take up this yajña process. Su-medhasaḥ. And another word is alpa-medhasaḥ, less brain substance. Tad bhavaty alpa-medhasām. Antavat tu phalaṁ teṣāṁ yad bhavaty alpa-medhasām (BG 7.23). They are doing all other things, but not yajña. Therefore alpa-medhasām: their brain substance is small."
(Srila Prabhupada Morning Walk, January 10, 1974, Los Angeles)
"There is one verse in Śrīmad-Bhāgavatam, kāmaṁ vavarṣa parjanyaḥ (SB 1.10.4). Parjanya means rainfall. Rainfall means it is supplying all the necessities of life. And this rainfall will be easy when there is yajña. And nobody is performing yajña; therefore nowadays rainfall is scarcity. In Europe recently I have seen, there is no rainfall, whole Europe. It is on the verge of drying everything. So this punishment will come in this Kali-yuga. There will be no rainfall, and there will be not sufficient food supply, and the government will simply levy taxes on different pleas, and people will be so much embarrassed that they will give up their hearth and home and flee away to the forest. It is stated. So therefore you must perform yajña. And that is very easy in this age. Yajñaiḥ saṅkīrtana-prāyair yajanti hi su-medhasaḥ (SB 11.5.32). You cannot perform the former yajñasa by sacrifice tons of ghee and grains because you have no sufficient food grains even. But still, if you chant this saṅkīrtana, that is yajña. Therefore you must take to saṅkīrtana-yajña. Yajñaiḥ saṅkīrtana-prāyair yajanti hi su-medhasaḥ. It is very easy."
(Srila Prabhupada Evening Darsana, December 3, 1976, Hyderabad)
"Regarding performance of Sankirtana yajna, this is explained in my book the Nectar of Devotion. Caitanya Mahaprabhu has given us the chanting of the Maha mantra: Hare Krishna Hare Krishna Krishna Krishna Hare Hare Hare Rama Hare Rama Rama Rama Hare Hare. It may be performed as sankirtan congregational chanting in public. This is done by our sankirtana parties that go daily into the streets in many cities of the world. Or this yajna may be performed quietly and privately with one's self by chanting on beads. This is known as Japa. So this I think can be performed by you very easily."
(Srila Prabhupada Letter, August 19, 1974)
"In this age the spiritual revolution was recommended by Lord Caitanya Mahaprabhu. He demonstrated that the Yuga Dharma for this age is the Sankirtan chanting of the holy names. If we want the degraded mass of people to be elevated, we must stop their sinful activity. To stop sinful activity one must purify the mind and the best process for purifying the mass mind is the chanting of the maha mantra Hare Krishna. This can be done in public where everyone has a chance to hear and be purified.
We experience that people are becoming more friendly and helping our movement in America simply because we are performing this sankirtan yajna. I hope you can understand this. This movement is authorized and confirmed by great acaryas as well as the sastras and also by Lord Caitanya Himself Who is the Supreme Personality of Godhead, non different from Krishna."
(Srila Prabhupada Letter, August 20, 1974)