If one supplies water to the root of a tree, all the parts of the tree, such as the leaves and branches, are automatically satisfied, and if one supplies food to the stomach, all the limbs of the body - the hands, legs, fingers, etc. - are nourished
SB Canto 4
My dear Vidura, carrier of bows and arrows, all the demigods who were performing the sacrifice took their bath at the confluence of the Ganges and the Yamunā after completing the yajña performance. Such a bath is called avabhṛtha-snāna. After thus becoming purified in heart, they departed for their respective abodes.
After Lord Śiva and, previously, Dakṣa, left the arena of sacrifice, the sacrifice was not stopped; the sages went on for many years in order to satisfy the Supreme Lord. The sacrifice was not destroyed for want of Śiva and Dakṣa, and the sages went on with their activities. In other words, it may be assumed that if one does not worship the demigods, even up to Lord Śiva and Brahmā, one can nevertheless satisfy the Supreme Personality of Godhead. This is also confirmed in Bhagavad-gītā (7.20). Kāmais tais tair hṛta jñānāḥ prapadyante 'nya-devatāḥ. Persons who are impelled by lust and desire go to the demigods to derive some material benefit. In his commentary on this Bhagavad-gītā verse, Viśvanātha Cakravartī Ṭhākura uses the very specific words naṣṭa-buddhayaḥ, meaning "persons who have lost their sense or intelligence." Only such persons care for demigods and want to derive material benefit from them. Of course, this does not mean that one should not show respect to the demigods; but there is no need to worship them. One who is honest may be faithful to the government, but he does not need to bribe the government servants. Bribery is illegal; one does not bribe a government servant, but that does not mean that one does not show him respect. Similarly, one who engages in the transcendental loving service of the Supreme Lord does not need to worship any demigod, nor does he have any tendency to show disrespect to the demigods. Elsewhere in Bhagavad-gītā (9.23) it is stated, ye 'py anya-devatā-bhaktā yajante śraddhayānvitāḥ. The Lord says that anyone who worships the demigods is also worshiping Him, but he is worshiping avidhi-pūrvakam, which means "without following the regulative principles." The regulative principle is to worship the Supreme Personality of Godhead. Worship of demigods may indirectly be worship of the Personality of Godhead, but it is not regulated. By worshiping the Supreme Lord, one automatically serves all the demigods because they are parts and parcels of the whole. If one supplies water to the root of a tree, all the parts of the tree, such as the leaves and branches, are automatically satisfied, and if one supplies food to the stomach, all the limbs of the body—the hands, legs, fingers, etc.—are nourished. Thus by worshiping the Supreme Personality of Godhead one can satisfy all the demigods, but by worshiping all the demigods one does not completely worship the Supreme Lord. Therefore worship of the demigods is irregular, and it is disrespectful to the scriptural injunctions.
In this age of Kali it is practically impossible to perform the deva-yajña, or sacrifices to the demigods. As such, in this age Śrīmad-Bhāgavatam recommends saṅkīrtana-yajña. Yajñaiḥ saṅkīrtana-prāyair yajanti hi sumedhasaḥ (SB 11.5.32). "In this age the intelligent person completes the performances of all kinds of yajñas simply by chanting Hare Kṛṣṇa, Hare Kṛṣṇa, Kṛṣṇa Kṛṣṇa, Hare Hare/ Hare Rāma, Hare Rāma, Rāma Rāma, Hare Hare." Tasmin tuṣṭe jagat tuṣṭaḥ: "When Lord Viṣṇu is satisfied, all the demigods, who are parts and parcels of the Supreme Lord, are satisfied."