Generally, the sacrifice is offered with clarified butter and grains, but with the progress of time, human society has produced varieties of goods by transforming materials supplied by God's material nature. Human society, therefore, must learn to offer sacrifices not only with clarified butter, but also with other manufactured goods in the propagation of the Lord's glory, and that will bring about perfection in human society.
(SRIMAD BHAGAVATAM-----2:1:37-----PURPORT).

It is very important to note in this connection how wealthy the inhabitants of Vṛndāvana were simply by raising cows. All the cowherd men belonged to the vaiśya community, and their business was to protect the cows and cultivate crops. By their dress and ornaments, and by their behavior, it appears that although they were in a small village, they still were rich in material possessions. They possessed such an abundance of various kinds of milk products that they were throwing butter lavishly on each other’s bodies without restriction. Their wealth was in milk, yogurt, clarified butter and many other milk products, and by trading their agricultural products, they were rich in various kinds of jewelry, ornaments and costly garments. Not only did they possess all these things, but they could give them away in charity lavishly, as did Nanda Mahārāja.
(KRSNA BOOK).

Fire is considered to be the tongue of the Personality of Godhead Viṣṇu, and oblations of grains and clarified butter offered to the fire are thus accepted by Him. That is the principle of all sacrifices, of which Lord Viṣṇu is the master. In other words, the satisfaction of Lord Viṣṇu includes the satisfaction of all demigods and other living beings.
(SRIMAD BHAGAVATAM-----3:14:9-----PURPORT).

The separated, material energy bewilders the living entities (jīvas), and thus they work very hard under its influence, not knowing that they are not fulfilling their mission in life. Unfortunately, most of them think that they are the body and should therefore enjoy the material senses irresponsibly since when death comes everything will be finished. This atheistic philosophy also flourished in India, where it was sometimes propagated by Cārvāka Muni, who said:
ṛṇaṁ kṛtvā ghṛtaṁ pibet yāvaj jīvet sukhaṁ jīvet
bhasmī-bhūtasya dehasya kutaḥ punar āgamano bhavet
His theory was that as long as one lives one should eat as much ghee as possible. In India, ghee (clarified butter) is a basic ingredient in preparing many varieties of food. Since everyone wants to enjoy nice food, Cārvāka Muni advised that one eat as much ghee as possible.
(SRI CAITANYA CARITAMRTA------ 1:7:119-----PURPORT).

Persons who profess to belong to some religious sect but who do not feel the presence of the Supreme Personality of Godhead in every living entity, and everywhere else, are in the mode of ignorance.
If, without this preliminary knowledge of the Lord's omnipresence, one simply attaches himself to the rituals in a temple, church or mosque, it is as if he were offering butter into ashes rather than into the fire. One offers sacrifices by pouring clarified butter into a fire and chanting Vedic mantras, but even if there are Vedic mantras and all conditions are favorable, if the clarified butter is poured on ashes, then such a sacrifice will be useless.

(SRIMAD BHAGAVATAM-----3:29:22-----PURPORT).

The Lord is generally known as go-brāhmaṇa-hitāya ca, which means that His first duty is to see to the welfare of the cows and the brāhmaṇas. Thus He used to give cows in charity to the brāhmaṇas, with opulent decorations and paraphernalia. Then, wishing for the welfare of all living entities, He would touch auspicious articles such as milk, honey, ghee (clarified butter), gold, jewels and fire.

(KRSNA BOOK).

Surabhi cows inhabit the spiritual world, and, as stated in Brahma-saṁhitā, Lord Kṛṣṇa is engaged in tending these cows: surabhīr abhipālayantam (Bs. 5.29). One can milk a surabhi cow as often as one likes, and the cow will deliver as much milk as one requires. Milk, of course, is necessary for the production of so many milk products, especiallyclarified butter, which is required for the performance of great sacrifices. Unless we are prepared to perform the prescribed sacrifices, our supply of the necessities of life will be checked. Bhagavad-gītā confirms that Lord Brahmā created human society along with yajña, the performance of sacrifice. Yajña means Lord Viṣṇu, the Supreme Personality of Godhead, and sacrifice means working for the satisfaction of the Supreme Personality of Godhead. In this age, however, it is very difficult to find qualified brāhmaṇas who can perform sacrifices as prescribed in the Vedas. Therefore it is recommended in Śrīmad-Bhāgavatam (yajñaiḥ saṅkīrtana-prāyaiḥ) that by performing saṅkīrtana-yajña and by satisfying the yajña-puruṣa, Lord Caitanya, one can derive all the results derived by great sacrifices in the past.

(SRIMAD BHAGAVATAM-----4:19:7-----PURPORT).

The brāhmaṇas said: Dear Lord, You are sacrifice personified. You are the offering of clarified butter, You are the fire, You are the chanting of Vedic hymns by which the sacrifice is conducted, You are the fuel, You are the flame, You are the kuśa grass, and You are the sacrificial pots. You are the priests who perform the yajña, You are the demigods headed by Indra, and You are the sacrificial animal. Everything that is sacrificed is You or Your energy.
In this statement Lord Viṣṇu's all-pervasiveness is partially explained. It is said in the Viṣṇu Purāṇa that as a fire situated in one place emanates its heat and illumination everywhere, so whatever we see within the material or spiritual worlds is nothing but a manifestation of different energies emanating from the Supreme Personality of Godhead. The brāhmaṇas' statement is that Lord Viṣṇu is everything—the fire, the offering, the clarified butter, the utensils, the place of sacrifice and the kuśa. He is everything. It is confirmed herein that the performance of saṅkīrtana-yajña in this age is as good as all other yajñas in all other ages. If one performs saṅkīrtana-yajña by chanting Hare Kṛṣṇa, Hare Kṛṣṇa, Kṛṣṇa Kṛṣṇa, Hare Hare/ Hare Rāma, Hare Rāma, Rāma Rāma, Hare Hare, there is no need to arrange elaborate paraphernalia for the prescribed sacrificial ceremonies recommended in the Vedas.

(SRIMAD BHAGAVATAM-----4:7:45-----TRANSLATION AND PURPORT).

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