"The knowledge of the self and Supreme Self is very confidential and mysterious, but such knowledge and specific realization can be understood if explained with their various aspects by the Lord Himself." Bhagavad-gītā gives us that general and specific knowledge of the self. The living entities are parts and parcels of the Lord, and therefore they are simply meant to serve the Lord. This consciousness is called Kṛṣṇa consciousness. So, from the very beginning of life one has to learn this Kṛṣṇa consciousness, and thereby one may become fully Kṛṣṇa conscious and act accordingly.
(Bhagavad-Gita----3:41-----purport).

The symptoms of the self-realized person are given herein. The first symptom is that he is not illusioned by the false identification of the body with his true self. He knows perfectly well that he is not this body, but is the fragmental portion of the Supreme Personality of Godhead. He is therefore not joyful in achieving something, nor does he lament in losing anything which is related to his body. This steadiness of mind is called sthira-buddhi, or self-intelligence. He is therefore never bewildered by mistaking the gross body for the soul, nor does he accept the body as permanent and disregard the existence of the soul. This knowledge elevates him to the station of knowing the complete science of the Absolute Truth, namely Brahman, Paramātmā and Bhagavān. He thus knows his constitutional position perfectly well, without falsely trying to become one with the Supreme in all respects. This is called Brahman realization, or self-realization. Such steady consciousness is called Kṛṣṇa consciousness.
(Bhagavad-Gita----5:20-----purport).

One who controls the mind (and therefore the senses as well) is called gosvāmī, or svāmī, and one who is controlled by the mind is called go-dāsa, or the servant of the senses. A gosvāmī knows the standard of sense happiness. In transcendental sense happiness, the senses are engaged in the service of Hṛṣīkeśa, or the supreme owner of the senses—Kṛṣṇa. Serving Kṛṣṇa with purified senses is called Kṛṣṇa consciousness. That is the way of bringing the senses under full control. What is more, that is the highest perfection of yoga practice.
(Bhagavad-Gita----6:26-----purport).

One should not be attached to the result of his work, but the result should be offered to Kṛṣṇa, and one should accept as prasādam the remnants of offerings to Kṛṣṇa. If one constructs a very big building for Kṛṣṇa and installs the Deity of Kṛṣṇa, one is not prohibited from living there, but it is understood that the proprietor of the building is Kṛṣṇa. That iscalled Kṛṣṇa consciousness. If, however, one is not able to construct a temple for Kṛṣṇa, one can engage himself in cleansing the temple of Kṛṣṇa; that is also kṛṣṇa-karma.
(Bhagavad-Gita----11:55-----purport).

Under the influence of material desire, the entity is born sometimes as a demigod, sometimes as a man, sometimes as a beast, as a bird, as a worm, as an aquatic, as a saintly man, as a bug. This is going on. And in all cases the living entity thinks himself to be the master of his circumstances, yet he is under the influence of material nature.
How he is put into such different bodies is explained here. It is due to association with the different modes of nature. One has to rise, therefore, above the three material modes and become situated in the transcendental position. That is called Kṛṣṇa consciousness. Unless one is situated in Kṛṣṇa consciousness, his material consciousness will oblige him to transfer from one body to another because he has material desires since time immemorial.
(Bhagavad-Gita----13:22-----purport).

All sacrifices are meant to please the Supreme Lord. The living entities who know this perfectly well are called demigods, godly or almost God. Since the living entity is part and parcel of the Supreme Lord, it is his duty to serve the Lord and please Him. The demigods are all attached to the Personality of Godhead, and for their pleasure the demon, who was a source of trouble to the world, was killed. Purified life is meant to please the Lord, and all sacrifices performed in purified life are called Kṛṣṇa consciousness.
(Srimad Bhagavatam-----3:19:30----purport).

Attachment cannot be killed; it has simply to be transferred. Attachment for material things is called material consciousness, and attachment for Kṛṣṇa or His devotee is called Kṛṣṇa consciousness. Consciousness, therefore, is the platform of attachment. It is clearly stated here that when we simply purify the consciousness from material consciousness to Kṛṣṇa consciousness, we attain liberation.
(Srimad Bhagavatam-----3:25:20----purport).

The vāsudeva stage is free from infringement by material desires and is the status in which one can understand the Supreme Personality of Godhead, or the objective which is described in the Bhagavad-gītā as adbhuta. This is another feature of the mahat-tattva. The vāsudeva expansion is also called Kṛṣṇa consciousness, for it is free from all tinges of material passion and ignorance. This clear state of understanding helps one to know the Supreme Personality of Godhead.
(Srimad Bhagavatam-----3:26:21----purport).

The appearance of consciousness after the appearance of false ego indicates that, from the beginning, material consciousness is under the mode of ignorance and that one therefore has to purify himself by purifying his consciousness. This purificatory process is called Kṛṣṇa consciousness. As soon as the consciousness is purified, the false ego disappears. Identification of the body with the self is called false identification, or false ego.
(Srimad Bhagavatam-----3:26:61----purport).

One should engage in the service of the Lord twenty-four hours a day, as confirmed in the Brahma-saṁhitā. The stage of premāñjana-cchurita can be attained by developing complete love. When one's love for the Supreme Personality of Godhead in devotional service is fully developed, one always sees the Lord, even without artificially meditating on His form. His vision is divine because he has no other engagement. At this stage of spiritual realization it is not necessary to engage the mind artificially. Since the meditation recommended in the lower stages is a means to come to the platform of devotional service, those already engaged in the transcendental loving service of the Lord are above such meditation. This stage of perfection is called Kṛṣṇa consciousness.
(Srimad Bhagavatam-----3:28:34----purport).

There is a difference between demoniac mentality and devotional mentality. Devotees know perfectly well that the goddess of fortune, who is the constant companion of Viṣṇu, or Nārāyaṇa, cannot be enjoyed by a living entity. This higher sense of understanding is called Kṛṣṇa consciousness. Nonetheless, everyone wants to become happy by imitating the prosperity of Nārāyaṇa. In this verse Purañjana states that the girl appears to be an ordinary woman. However, since he is attracted by her, he requests that she become as happy as the goddess of fortune by associating with him. Thus he introduces himself as a great king with great influence so that she might accept him as her husband and be as happy as the goddess of fortune. To desire to enjoy this material world as a subordinate of the Supreme Personality of Godhead is godly. The demons, however, want to enjoy this material world without considering the Supreme Personality of Godhead. This is the difference between a demon and a demigod.
(Srimad Bhagavatam-----4:25:29----purport).

Śrīla Bhaktivinoda Ṭhākura considers the brahma-bhūta stage in two divisions—svarūpa-gata and vastu-gata. One who has understood Kṛṣṇa in truth but is still maintaining some material connection is known to be situated in his svarūpa, his original consciousness. When that original consciousness is completely spiritual, it is called Kṛṣṇa consciousness. One who lives in such consciousness is actually living in Vṛndāvana. He may live anywhere; material location doesn’t matter. When by the grace of Kṛṣṇa one thus advances, he becomes completely uncontaminated by the material body and mind and at that time factually lives in Vṛndāvana.
(Sri Caitanya Caritamrta----2:8:139----purport).

It is said that it is the nature of a devotee to constantly apply his mind, energy, words, ears, etc., in hearing and chanting about Kṛṣṇa. This is called Kṛṣṇa consciousness, and for one who is rapt in hearing and chanting about Kṛṣṇa, the subject matter never becomes hackneyed or old. That is the significance of transcendental subject matter in contrast to material subject matter. Material subject matter becomes stale, and one cannot hear a certain subject for a long time; he wants change. But as far as transcendental subject matter is concerned, it is called nitya-nava-navāyamāna. This means that one can go on chanting and hearing about the Lord and never feel tired but remain fresh and eager to hear more and more.
(Krsna Book).

The mind is nothing but the energy of Kṛṣṇa. Actually, any person who can think, feel and will cannot be separated from Kṛṣṇa. But the stage in which he can understand his eternal relationship with Kṛṣṇa is called Kṛṣṇa consciousness. The diseased condition in which he cannot understand his eternal relationship with Kṛṣṇa is the contaminated stage, or māyā.
(Krsna Book).

Just as the shining particles of the sun's rays always exist with the sun, the living entities exist eternally as parts and parcels of the Supreme Personality of Godhead. But just as the sun rays are sometimes covered by a cloud, which is created by the sun, so the conditioned souls, although eternally existing as parts of the Supreme Lord, are sometimes put within the cloud of the material concept of life, in the darkness of ignorance. The whole Vedic process is to alleviate that darkened condition. Ultimately, when the senses and mind of the conditioned being are fully purified, he comes to his original position, called Kṛṣṇa consciousness, and that is liberation.
(Krsna Book).

Talking of Kṛṣṇa or singing of Kṛṣṇa is called kīrtana. Lord Caitanya recommends, kīrtanīyaḥ sadā hariḥ (CC.1:17:31), which means always thinking and talking of Kṛṣṇa and nothing else. That is called Kṛṣṇa consciousness. Kṛṣṇa consciousness is so sublime that anyone who takes to this process is elevated to the highest perfection of life—far, far beyond the concept of liberation. In the Bhagavad-gītā, therefore, Kṛṣṇa advises everyone always to think of Him, render devotional service to Him, worship Him and offer obeisances to Him. In this way a devotee becomes fully Kṛṣṇa-ized and, being always situated in Kṛṣṇa consciousness, ultimately goes back to Kṛṣṇa.
(Krsna Book).

If by the evolutionary process of philosophical life one happens to reach the platform of intellectual life and understands that he is not this material body but a spiritual soul, he is situated in the vijñāna-maya stage. Then, by evolution in spiritual life, he comes to the understanding of the Supreme Lord, or the Supreme Soul. When one develops his relationship with Him and executes devotional service, that stage of life is called Kṛṣṇa consciousness, the ānanda-maya stage. Ānanda-maya is the blissful life of knowledge and eternity. As it is said in the Vedānta-sūtra, ānanda-mayo ’bhyāsāt. The Supreme Brahman and the subordinate Brahman, or the Supreme Personality of Godhead and the living entities, are both joyful by nature.
(Krsna Book).