SB 2.6.26
nama-dheyani mantras ca
daksinas ca vratani ca
devatanukramah kalpah
sankalpas tantram eva ca
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Other necessities include invoking the different names of the demigods by specific hymns and vows of recompense, in accordance with the particular scripture, for specific purposes and by specific processes.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
The whole process of offering sacrifice is under the category of fruitive action, and such activities are extremely scientific. They mainly depend on the process of vibrating sounds with a particular accent. It is a great science, and due to being out of proper use for more than four thousand years, for want of qualified brahmanas such performances of sacrifice are no longer effective. Nor are they recommended in this fallen age. Any such sacrifice undertaken in this age as a matter of show may simply be a cheating process by the clever priestly order. But such a show of sacrifices cannot be effective at any stage. Fruitive action is being carried on by the help of material science and to a little extent by gross material help, but the materialists await a still more subtle advancement in the process of vibrating sounds on which the Vedic hymns are established. Gross material science cannot divert the real purpose of human life. It can only increase the artificial needs of life without any solution to the problems of life; therefore the way of materialistic life leads to the wrong type of human civilization. Since the ultimate aim of life is spiritual realization, the direct way of invoking the holy name of the Lord, as mentioned above, is precisely recommended by Lord Caitanya, and people of the modern age can easily take advantage of this simple process, which is tenable for the condition of the complicated social structure.