Krishna is realized in different degrees as Brahman, Paramatma and the Supreme Personality of Godhead. Krishna consciousness means, concisely, to be always engaged in the transcendental loving service of the Lord. But those who are attached to the impersonal Brahman or the localized Supersoul are also partially Krishna conscious, because impersonal Brahman is the spiritual ray of Krishna and Supersoul is the all-pervading partial expansion of Krishna. Thus the impersonalist and the meditator are also indirectly Krishna conscious. A directly Krishna conscious person is the topmost transcendentalist because such a devotee knows what is meant by Brahman or Paramatma. His knowledge of the Absolute Truth is perfect, whereas the impersonalist and the meditative yogi are imperfectly Krishna conscious.
Nevertheless, all of these are instructed herewith to be constantly engaged in their particular pursuits so that they may come to the highest perfection sooner or later. The first business of a transcendentalist is to keep the mind always on Krishna. One should always think of Krishna and not forget Him even for a moment. Concentration of the mind on the Supreme is called samadhi, or trance. In order to concentrate the mind, one should always remain in seclusion and avoid disturbance by external objects. He should be very careful to accept favorable and reject unfavorable conditions that affect his realization. And, in perfect determination, he should not hanker after unnecessary material things that entangle him by feelings of possessiveness.
All these perfections and precautions are perfectly executed when one is directly in Krishna consciousness because direct Krishna consciousness means self-abnegation, wherein there is very little chance for material possessiveness. Srila Rupa Gosvami characterizes Krishna consciousness in this way:
anasaktasya visayan yatharham upayunjatah
nirbandhah Krishna-sambandhe yuktam vairagyam ucyate
prapancikataya buddhya hari-sambandhi-vastunah
mumuksubhih parityago vairagyam phalgu kathyate
"When one is not attached to anything, but at the same time accepts everything in relation to Krishna, one is rightly situated above possessiveness. On the other hand, one who rejects everything without knowledge of its relationship to Krishna is not as complete in his renunciation."
A Krishna conscious person well knows that everything belongs to Krishna, and thus he is always free from feelings of personal possession. As such, he has no hankering for anything on his own personal account. He knows how to accept things in favor of Krishna consciousness and how to reject things unfavorable to Krishna consciousness. He is always aloof from material things because he is always transcendental, and he is always alone, having nothing to do with persons not in Krishna consciousness. Therefore a person in Krishna consciousness is the perfect yogi.