The essence of knowledge is that there are two kinds of vastu, or substances, One is real, and the other, being illusory or temporary, is sometimes called nonfactual. One must consider these two kinds of existence. The real tattva, or truth, consists of Brahman, Paramatma, and Bhagavan. As stated in Srimad-Bhagavatam (1.2.11):

The categories of emanations from the nonsubstance are twoactivities and forbidden activities (karma and vikarma). Karma refers to the pious life or material activities performed during the day and the mental activities of dreams at night. These are more or less desired activities. Vikarma, however, refers to illusory activities, which are something like the will-o-the-wisp. These are activities that have no meaning. For example, modern scientists imagine that life can be produced from chemical combinations, and they are very busy trying to prove this in laboratories throughout the world, although no one in history has been able to produce the substance of life from material combinations. Such activities are called vikarma.

All material activities are actually illusory, and progress in illusion is simply a waste of time. These illusory activities are called akarya, and one must learn of them from the instructions of the Supreme Personality of Godhead. As stated in Bhagavad-gita (4.17):

Herein it is said, aham vai sarva-bhutani: the Lord is everything (sarva-bhutani), including the living entities and the material or physical elements. As the Lord says in Bhagavad-gita (7.45):

Again, the Lord, as the Supersoul, guides the living entities who are conditioned by the physical atmosphere. Therefore he is called bhutatma bhuta-bhavanah. He gives the living entity the intelligence with which to improve his position so that he may return home, back to Godhead, or if he does not want to go back to Godhead, the Lord gives him the intelligence with which to improve his material position. This is confirmed by the Lord Himself in Bhagavad-gita (15.15). Sarvasya caham hrdi sannivisto mattah smrtir jnanam apohanam ca: I am seated in everyones heart, and from Me come remembrance, knowledge and forgetfulness. From within, the Lord gives the living being the intelligence with which to work. Therefore the previous verse said that after the Supreme Personality of Godhead endeavors, our endeavors begin. We cannot independently endeavor or act upon anything. Therefore the Lord is bhuta-bhavanah.

Another specific feature of the knowledge given in this verse is that sabda-brahma is also a form of the Supreme Lord. In His eternal, blissful form, Lord Krsna is accepted by Arjuna as param brahma. A living entity in the conditioned stage accepts something illusory as substantial. This is called maya or avidyaignorance. Therefore according to the Vedic knowledge, one must become a devotee, and one must then distinguish between avidya and vidya, which are elaborately explained in the Isopanisad. When one is actually on the platform of vidya, he can personally understand the Personality of Godhead in His forms like those of Lord Rama, Lord Krsna and Sankarsana. The Vedic knowledge is described as the breathing of the Supreme Lord, and activities begin on the basis of Vedic knowledge. Therefore the Lord says that when He endeavors or breathes, the material universes come into existence, and various activities gradually develop. The Lord says in Bhagavad-gita, pranavah sarva-vedesu: I am the syllable om in all the Vedic mantras. Vedic knowledge begins with the vibration of the transcendental sound pranava, omkara. The same transcendental sound is Hare Krsna, Hare Krsna, Krsna Krsna, Hare Hare/ Hare Rama, Hare Rama, Rama Rama, Hare Hare. Abhinnatvan nama-naminoh: there is no difference between the holy name of the Lord and the Lord Himself.