The Supreme Personality of Godhead said: O Pārtha, when a man gives up all varieties of desire for sense gratification, which arise from mental concoction, and when his mind, thus purified, finds satisfaction in the self alone, then he is said to be in pure transcendental consciousness."
The Bhāgavatam affirms that any person who is fully in Kṛṣṇa consciousness, or devotional service of the Lord, has all the good qualities of the great sages, whereas a person who is not so transcendentally situated has no good qualifications, because he is sure to be taking refuge in his own mental concoctions. Consequently, it is rightly said herein that one has to give up all kinds of sense desire manufactured by mental concoction. Artificially, such sense desires cannot be stopped. But if one is engaged in Kṛṣṇa consciousness, then, automatically, sense desires subside without extraneous efforts. Therefore, one has to engage himself in Kṛṣṇa consciousness without hesitation, for this devotional service will instantly help one onto the platform of transcendental consciousness. The highly developed soul always remains satisfied in himself by realizing himself as the eternal servitor of the Supreme Lord. Such a transcendentally situated person has no sense desires resulting from petty materialism; rather, he remains always happy in his natural position of eternally serving the Supreme Lord.
(Bhagavad-Gita-----2:55-----purport).

Anything done under the direction of Kṛṣṇa is transcendental. It cannot be contaminated by material reactions, which may be auspicious or inauspicious. The conception that there are things auspicious and inauspicious in the material world is more or less a mental concoction because there is nothing auspicious in the material world. Everything is inauspicious because the very material nature is inauspicious. We simply imagine it to be auspicious. Real auspiciousness depends on activities in Kṛṣṇa consciousness in full devotion and service. Therefore if we at all want our activities to be auspicious, then we should work under the directions of the Supreme Lord.
(Bhagavad-Gita-----10:3-----purport).

The word śraddhā, or "faith," is very significant in this verse. Śraddhā, or faith, originally comes out of the mode of goodness. One's faith may be in a demigod or some created God or some mental concoction. One's strong faith is supposed to be productive of works of material goodness. But in material conditional life, no works are completely purified. They are mixed. They are not in pure goodness. Pure goodness is transcendental; in purified goodness one can understand the real nature of the Supreme Personality of Godhead. As long as one's faith is not completely in purified goodness, the faith is subject to contamination by any of the modes of material nature.
(Bhagavad-Gita-----17:3-----purport).

There is no profit in denying the supremacy of the Lord, who is the controller of all energies, but one should be constitutionally situated in one's own glory, namely to be situated in the pure consciousness of being the eternal servitor of the Lord. In his conditional life the living entity is servant of the illusory māyā, and in his liberated state he is the pure, unqualified servant of the Lord. To become untinged by the modes of material nature is the qualification for entering into the service of the Lord. As long as one is a servant of mental concoctions, one cannot be completely free from the disease of "I" and "mine."
(Srimad Bhagavatam-----2:9:3-----purport).

The devotees of the Lord see the wonderful dexterity in everything with which they come in contact in all circumstances of eating, sleeping, working, etc. A small banyan fruit contains thousands of small seeds, and each seed holds the potency of another tree, which again holds the potency of many millions of such fruits as causes and effects. So the trees and seeds engage the devotees in meditation about the activities of the Lord, while the mundane wranglers waste time in dry speculation and mental concoction, which are fruitless in both this life and the next. In spite of their pride in speculation, they can never appreciate the simple potential activities of the banyan tree. Such speculators are poor souls destined to remain in matter perpetually.
(Srimad Bhagavatam-----3:6:39-----purport).

The whole trouble of the living entity in material existence is that he has an independent conception of life. He is always dependent on the rules of the Supreme Lord, in both the conditioned and liberated states, but by the influence of the external energy the conditioned soul thinks himself independent of the supremacy of the Personality of Godhead. His constitutional position is to dovetail himself with the desire of the supreme will, but as long as he does not do so, he is sure to drag on in the shackles of material bondage. As stated in Bhagavad-gītā (2.55), prajahāti yadā kāmān sarvān pārtha mano-gatān: he has to give up all sorts of plans manufactured by mental concoction. The living entity has to dovetail himself with the supreme will. That will help him to get out of the entanglement of material existence.
(Srimad Bhagavatam-----3:9:9-----purport).

As long as one acts on his own account, he is subject to all the material perceptions of so-called happiness and distress. Actually there is no happiness. Just as there is no happiness in any of the activities of a madman, so in material activities the mental concoctions of happiness and distress are false. Actually everything is distress.
(Srimad Bhagavatam-----3:28:36-----purport).

Devotional service in Kṛṣṇa consciousness cannot be performed blindly due to material emotion or mental concoction. It is specifically mentioned here that one has to perform devotional service in full knowledge by visualizing the Absolute Truth. We can understand about the Absolute Truth by evolving transcendental knowledge, and the result of such transcendental knowledge will be manifested by renunciation. That renunciation is not temporary or artificial, but is very strong. It is said that development of Kṛṣṇa consciousness is exhibited by proportionate material detachment, or vairāgya. If one does not separate himself from material enjoyment, it is to be understood that he is not advancing in Kṛṣṇa consciousness.
(Srimad Bhagavatam-----3:27:22-----purport).

The significance of advancement in transcendental knowledge and detachment from material attraction is exhibited in the personality of a highly advanced devotee. For him there is nothing agreeable or disagreeable because he does not act in any way for his personal sense gratification. Whatever he does, whatever he thinks, is for the satisfaction of the Personality of Godhead. Either in the material world or in the spiritual world, his equipoised mind is completely manifested. He can understand that in the material world there is nothing good; everything is bad due to its being contaminated by material nature. The materialists' conclusions of good and bad, moral and immoral, etc., are simply mental concoction or sentiment. Actually there is nothing good in the material world.
(Srimad Bhagavatam-----3:32:24-----purport).

Real knowledge is revealed to a devotee only when he comes to the right conclusion about life by the grace of the Lord. Our creation of friends and enemies within this material world is something like dreaming at night. In dreams we create so many things out of various impressions in the subconscious mind, but all such creations are simply temporary and unreal. In the same way, although apparently we are awake in material life, because we have no information of the soul and the Supersoul, we create many friends and enemies simply out of imagination. Śrīla Kṛṣṇadāsa Kavirāja Gosvāmī says that within this material world or material consciousness, good and bad are the same. The distinction between good and bad is simply a mental concoction. The actual fact is that all living entities are sons of God, or by-products of His marginal energy. Because of our being contaminated by the modes of material nature, we distinguish one spiritual spark from another.
(Srimad Bhagavatam-----4:9:33-----purport).