The Lord's potencies are innumerable. As He lies down in the water of devastation, I am born as the total universal energy from the navel lake in which the lotus sprouts. I am now engaged in manifesting His diverse energies in the form of the cosmic manifestation. I therefore pray that in the course of my material activities I may not be deviated from the vibration of the Vedic hymns.
Every person engaged in the transcendental loving service of the Lord in this material world is prone to so many material activities, and if one is not strong enough to protect himself against the onslaught of material affection, he may be diverted from the spiritual energy. In the material creation Brahmā has to create all kinds of living entities with bodies suitable to their material conditions. Brahmā wants to be protected by the Lord because he has to contact many, many vicious living entities. An ordinary brāhmaṇa may fall from the brahma-tejas, or the power of brahminical excellence, due to his association with many fallen, conditioned souls. Brahmā, as the supermost brāhmaṇa, is afraid of such a falldown, and therefore he prays to the Lord for protection. This is a warning for one and all in the spiritual advancement of life. Unless one is sufficiently protected by the Lord, he may fall down from his spiritual position; therefore one has to pray constantly to the Lord for protection and the blessing to carry out one's duty. Lord Caitanya also entrusted His missionary work to His devotees and assured them of His protection against the onslaught of material affection. The path of spiritual life is stated in the Vedas to be like the edge of a sharpened razor. A little inattentiveness may at once create havoc and bloodshed, but one who is a completely surrendered soul, always seeking protection from the Lord in the discharge of his entrusted duties, has no fear of falling into material contamination.
(Srimad Bhagavatam--3:9:24--translation and purport).

Lord Kṛṣṇa says in the Bhagavad-gītā that He is the source of everything, but envious and cunning people try to refute this fact. Thus He appeared as Lord Caitanya and taught that Lord Kṛṣṇa is the source of everything. There is no difference between the instructions of Lord Kṛṣṇa and those of Lord Caitanya. The object of worship is the same. Still, the unfortunate people of this age refuse to accept these teachings. Trying to give them Kṛṣṇa consciousness is, as the well-known expression goes, like "casting pearls before a herd of swine." The human beings afflicted by Kali-yuga are like a herd of swine. The Lord has shown them boundless mercy by widely teaching the science of devotional service to Kṛṣṇa, which is rarely attained even by Lord Brahmā. Yet because it has been so easy for them to come by this precious and rare commodity, they have abused the mercy shown them. This is another manifestation of their misfortune. By teaching them the science of self-realization, Lord Kṛṣṇa has twice personally tried to save the people of this age from groveling in carnal pleasures, and both times they have converted those divine instructions into a means and an excuse for pursuing sense gratification.
When presented with a colorful glass doll and a diamond, a child will naturally be attracted to the doll and not the priceless jewel. Similarly, the people of Kali-yuga, endowed as they are with limited intelligence, have rejected the priceless diamond of devotional service to Kṛṣṇa and instead chosen the cheap doll of fruitive activity and dry speculation. Just as the child cannot comprehend that the invaluable diamond can purchase many thousands of cheap glass dolls, so the less intelligent people of Kali-yuga cannot understand that kṛṣṇe bhakti kaile sarva-karma-kṛta haya: "By rendering transcendental devotional service to Lord Kṛṣṇa, one automatically performs all subsidiary activities."
Those who know the science of Kṛṣṇa consciousness automatically know of subsidiary subjects like fruitive activity, speculative knowledge, yoga, charity, penance, austerity, and chanting mantras. Lord Kṛṣṇa confirms this in the Śrīmad-Bhāgavatam:
By executing devotional service to Me, My devotees easily acquire everything that can be attained by performing penances, fruitive activity, philosophical speculation, renunciation, yoga, charity, religiosity, and other pious acts.
(Renunciation Through Wisdom).