The conviction that Kṛṣṇa is all in all is established when one hears the transcendental message from the undisturbed ācārya with faith and love. One who has no faith in or love for Lord Kṛṣṇa cannot be convinced of this simple truth. Those who are faithless are described in the Bhagavad-gītā (9.11) as mūḍhas-fools or asses. It is said that the mūḍhas deride the Personality of Godhead because they do not have complete knowledge from the undisturbed ācārya. One who is disturbed by the whirlpool of material energy is not qualified to become an ācārya.
Before hearing the Bhagavad-gītā, Arjuna was disturbed by the material whirlpool, by his affection for his family, society and community. Thus Arjuna wanted to become a philanthropic, nonviolent man of the world. But when he became budha by hearing the Vedic knowledge of the Bhagavad-gītā from the Supreme Person, he changed his decision and became a worshiper of Lord Śrī Kṛṣṇa, who had Himself arranged the Battle of Kurukṣetra. Arjuna worshiped the Lord by fighting with his so-called relatives, and in this way he became a pure devotee of the Lord. Such accomplishments are possible only when one worships the real Kṛṣṇa and not some fabricated "Kṛṣṇa" invented by foolish men who are without knowledge of the intricacies of the science of Kṛṣṇa described in the Bhagavad-gītā and Śrīmad-Bhāgavatam.
According to the Vedānta-sūtra, sambhūta is the source of birth and sustenance, as well as the reservoir that remains after annihilation (janmādy asya yataḥ (SB 1.1.1). The Śrīmad-Bhāgavatam, the natural commentary on the Vedānta-sūtra by the same author, maintains that the source of all emanations is not like a dead stone but is abhijña, or fully conscious. The primeval Lord, Śrī Kṛṣṇa, also says in the Bhagavad-gītā (BG 7.26) that He is fully conscious of past, present and future and that no one, including demigods such as Śiva and Brahmā, knows Him fully. Certainly half-educated "spiritual leaders" who are disturbed by the tides of material existence cannot know Him fully. They try to make some compromise by making the mass of humanity the object of worship, but they do not know that such worship is only a myth because the masses are imperfect. The attempt by these so-called spiritual leaders is something like pouring water on the leaves of a tree instead of the root. The natural process is to pour water on the root, but such disturbed leaders are more attracted to the leaves than the root. Despite their perpetually watering the leaves, however, everything dries up for want of nourishment.
Śrī Īśopaniṣad advises us to pour water on the root, the source of all germination. Worship of the mass of humanity by rendering bodily service, which can never be perfect, is less important than service to the soul. The soul is the root that generates different types of bodies according to the law of karma. To serve human beings by medical aid, social help and educational facilities while at the same time cutting the throats of poor animals in slaughterhouses is no service at all to the soul, the living being.
The living being is perpetually suffering in different types of bodies from the material miseries of birth, old age, disease and death. The human form of life offers one a chance to get out of this entanglement simply by reestablishing the lost relationship between the living entity and the Supreme Lord. The Lord comes personally to teach this philosophy of surrender unto the Supreme, the sambhūta. Real service to humanity is rendered when one teaches surrender to and worship of the Supreme Lord with full love and energy. That is the instruction of Śrī Īśopaniṣad in this mantra.
The simple way to worship the Supreme Lord in this age of disturbance is to hear and chant about His great activities. The mental speculators, however, think that the activities of the Lord are imaginary; therefore they refrain from hearing of them and invent some word jugglery without any substance to divert the attention of the innocent masses of people. Instead of hearing of the activities of Lord Kṛṣṇa, such pseudo spiritual masters advertise themselves by inducing their followers to sing about them. In modern times the number of such pretenders has increased considerably, and it has become a problem for the pure devotees of the Lord to save the masses of people from the unholy propaganda of these pretenders and pseudo incarnations.