The resolute purpose of a person in Kṛṣṇa consciousness is based on knowledge. Vāsudevaḥ sarvam iti sa mahātmā su-durlabhaḥ: a person in Kṛṣṇa consciousness is the rare good soul who knows perfectly that Vāsudeva, or Kṛṣṇa, is the root of all manifested causes. As by watering the root of a tree one automatically distributes water to the leaves and branches, so by acting in Kṛṣṇa consciousness one can render the highest service to everyone—namely self, family, society, country, humanity, etc. IfKṛṣṇa is satisfied by one's actions, then everyone will be satisfied.
(Bhagavad-Gita----2:41----purport).

Only misers desire to enjoy the fruit of their own work just to be further entangled in material bondage. Except for work in Kṛṣṇa consciousness, all activities are abominable because they continually bind the worker to the cycle of birth and death. One should therefore never desire to be the cause of work. Everything should be done in Kṛṣṇa consciousness, for the satisfaction of Kṛṣṇa. Misers do not know how to utilize the assets of riches which they acquire by good fortune or by hard labor. One should spend all energies working in Kṛṣṇa consciousness, and that will make one's life successful.
(Bhagavad-Gita----2:49----purport).

One who is situated in this perfect stage knows that because Kṛṣṇa is the proprietor of everything, everything must be used for the satisfaction of Kṛṣṇa. Arjuna did not want to fight for his own sense satisfaction, but when he became fully Kṛṣṇa conscious he fought because Kṛṣṇa wanted him to fight. For himself there was no desire to fight, but for Kṛṣṇa the same Arjuna fought to his best ability. Real desirelessness is desire for the satisfaction of Kṛṣṇa, not an artificial attempt to abolish desires. The living entity cannot be desireless or senseless, but he does have to change the quality of the desires.
(Bhagavad-Gita----2:71----purport).

Nothing should be performed for sense gratification, but everything should be done for the satisfaction of Kṛṣṇa. This practice will not only save one from the reaction of work, but also gradually elevate one to transcendental loving service of the Lord, which alone can raise one to the kingdom of God.
(Bhagavad-Gita----3:9----purport).

A person in Kṛṣṇa consciousness and a person not in Kṛṣṇa consciousness are differentiated by different desires. A Kṛṣṇa conscious person does not do anything which is not conducive to development of Kṛṣṇa consciousness. He may even act exactly like the ignorant person, who is too much attached to material activities, but one is engaged in such activities for the satisfaction of his sense gratification, whereas the other is engaged for the satisfaction of Kṛṣṇa. Therefore, the Kṛṣṇa conscious person is required to show the people how to act and how to engage the results of action for the purpose of Kṛṣṇa consciousness.
(Bhagavad-Gita----3:25----purport).

The duality of the material world is felt in terms of heat and cold, or misery and happiness. A Kṛṣṇa conscious person is above duality because he does not hesitate to act in any way for the satisfaction of Kṛṣṇa. Therefore he is steady both in success and in failure. These signs are visible when one is fully in transcendental knowledge.
(Bhagavad-Gita----4:22----purport).

When a person is fully engaged in the transcendental loving service of the Lord, he is pleased in himself, and thus he is no longer engaged in sense gratification or in fruitive activities. Otherwise, one must be engaged in sense gratification, since one cannot live without engagement. Without Kṛṣṇa consciousness, one must be always seeking self-centered or extended selfish activities. But a Kṛṣṇa conscious person can do everything for the satisfaction of Kṛṣṇa and thereby be perfectly detached from sense gratification.
(Bhagavad-Gita----6:4----purport).

One should work only for Kṛṣṇa. It does not matter in what kind of work one engages, but that work should be done only for Kṛṣṇa. That is the standard of devotional service. The devotee does not desire any achievement other than pleasing the Supreme Personality of Godhead. His life's mission is to please Kṛṣṇa, and he can sacrifice everything forKṛṣṇa's satisfaction, just as Arjuna did in the Battle of Kurukṣetra.
(Bhagavad-Gita----12:6-7----purport).

One should be sympathetic to the propagation of Kṛṣṇa consciousness. There are many devotees who are engaged in the propagation of Kṛṣṇa consciousness, and they require help. So, even if one cannot directly practice the regulative principles of bhakti-yoga, he can try to help such work. Every endeavor requires land, capital, organization and labor. Just as in business one requires a place to stay, some capital to use, some labor and some organization to expand, so the same is required in the service of Kṛṣṇa. The only difference is that in materialism one works for sense gratification. The same work, however, can be performed for the satisfaction of Kṛṣṇa, and that is spiritual activity.
(Bhagavad-Gita----12:10----purport).

The Sanskrit word mat-paraḥ is very important in this verse. It indicates that one has no goal in life save and except acting in Kṛṣṇa consciousness just to satisfy Kṛṣṇa. And while working in that way, one should think of Kṛṣṇa only: "I have been appointed to discharge this particular duty by Kṛṣṇa." While acting in such a way, one naturally has to think of Kṛṣṇa. This is perfect Kṛṣṇa consciousness.
(Bhagavad-Gita----18:57----purport).

A person who has attained the paramahaṁsa stage knows very well the distinction between matter and spirit. He is not at all interested in gratifying the material senses, for he is always deriving pleasure from devotional service to the Lord. He is not very anxious to protect his material body. Being satisfied with whatever he attains by the grace of the Lord, he is completely independent of material happiness and distress, and thus he is transcendental to all regulative principles. Sometimes he accepts severe austerities, and sometimes he accepts material opulence. His only concern is to satisfy Kṛṣṇa, and for that purpose he can do anything and everything, without reference to the regulative principles. He is never to be equated with materialistic men, nor is he subject to the judgments of such men.
(Srimad Bhagavatam----7:13--summary).

For a devotee, there cannot be worship of others or demigod worship. A pure devotee does not engage himself in such pseudo devotional service. He is interested only in satisfying Kṛṣṇa. If one lives only for the satisfaction of Kṛṣṇa, it does not matter whether he belongs to this order of life or that order of life. One's only business should be to satisfy Kṛṣṇa. This process is completely manifest in the activities of the Kṛṣṇa consciousness movement. It has been actually proved that the entire world can accept devotional service without failure. One simply has to follow the instructions of the representative of Kṛṣṇa.
(Sri Caitanya Caritamrta----2:19:167----purport).

To desire material opulence while engaging in devotional service is foolish. Although the person may be foolish, Kṛṣṇa, being all-intelligent, engages him in His devotional service in such a way that he gradually forgets material opulence. The point is that we should not try to exchange loving service for material prosperity. If we are actually surrendered to the lotus feet of Kṛṣṇa, our only desire should be to satisfy Kṛṣṇa. That is pure Kṛṣṇa consciousness.
(Sri Caitanya Caritamrta----2:22:39----purport).

Karmīs think that the material body is an instrument for material enjoyment, and that is why they work extremely hard. A devotee, however, has no such desires. A devotee always engages wholeheartedly in the service of the Lord, forgetting about bodily conceptions and bodily activities. The body of a karmī is called material because the karmī, being too absorbed in material activities, is always eager to enjoy material facilities, but the body of a devotee who tries his best to work very hard for the satisfaction of Kṛṣṇa by fully engaging in the Lord's service must be accepted as transcendental. Whereas karmīs are interested only in the personal satisfaction of their senses, devotees work for the satisfaction of the Supreme Lord. Therefore one who cannot distinguish between devotion and ordinary karma may mistakenly consider the body of a pure devotee material. One who knows does not commit such a mistake.
(Sri Caitanya Caritamrta----3:4:173----purport).

However, one should generally accept the following principles to properly execute devotional service: (1) take shelter of a bona fide spiritual master, (2) receive initiation from the spiritual master, (3) serve the spiritual master, (4) inquire and learn love from the spiritual master, (5) follow in the footsteps of holy persons devoted to the transcendental loving service of the Lord, (6) prepare to give up all kinds of enjoyment and miseries for the satisfaction of Kṛṣṇa, (7) live in a place where Kṛṣṇa had His pastimes, (8) be satisfied by whatever is sent by Kṛṣṇa for the maintenance of the body and hanker for no more, (9) observe fasting on Ekādaśī day (this occurs on the eleventh day after the full moon and the eleventh day after the new moon. On such days no grains, cereals or beans are eaten; simply vegetables and milk are moderately taken, and chanting Hare Kṛṣṇa and reading scriptures are increased.), (10) show respect to devotees, cows and sacred trees like the banyan tree.
(Teachings of Lord Caitanya).

Lord Caitanya, describing the symptoms of a person who has developed from faith to the stage of bhāva, states that such a person is never agitated even if there are causes for agitation. Nor does such a person waste his time even for a moment; he is always anxious to do something for Kṛṣṇa. Even if he has no engagement, he will find some work to do for Kṛṣṇa's satisfaction. Nor does such a person like anything which is not connected with Kṛṣṇa. Although he is situated in the best position, he does not hanker after honor or personal respect. He is confident in his work, and he is never under the impression that he is not making progress toward the supreme goal of life-going back to Godhead.
(Teachings of Lord Caitanya).