SB 11.2.36

kāyena vācā manasendriyair vā
 buddhyātmanā vānusṛta-svabhāvāt
karoti yad yat sakalaṁ parasmai
 nārāyaṇāyeti samarpayet tat
Synonyms: 
kāyena — with the body; vācā — speech; manasā — mind; indriyaiḥ — senses; — or; buddhyā — with the intelligence; ātmanā — the purified consciousness; — or; anusṛta — followed; svabhāvāt — according to one’s conditioned nature; karoti — one does; yat yat — whatever; sakalam — all; parasmai — to the Supreme; nārāyaṇāya iti — thinking, “This is for Nārāyaṇa”; samarpayet — he should offer; tat — that.
Translation: 
In accordance with the particular nature one has acquired in conditioned life, whatever one does with body, words, mind, senses, intelligence or purified consciousness one should offer to the Supreme, thinking, “This is for the pleasure of Lord Nārāyaṇa.”
Purport: 

Śrīla Bhaktisiddhānta Sarasvatī Ṭhākura has commented in this regard that a person who engages all the sensory activities of his body, mind, words, intelligence, ego and consciousness in the service of the Supreme Lord cannot be considered to be on the same level as a karmī working for his personal sense gratification. Although apparently still a conditioned soul, one who offers the fruits of all his activities to the Lord can no longer be touched by the countless miseries that arise from the reactions to materialistic activities.

Because of enmity against the Supreme Personality of Godhead and His omnipotent authority, the conditioned living entity performs activities against the order of the Lord. Yet self-realized souls continue to perform all types of work within this world to carry out the mission of the Supreme Lord. According to Śrīla Bhaktisiddhānta Sarasvatī Ṭhākura, those karmīs who are sufficiently pious follow the example of the self-realized souls by trying to offer the fruits of their own duties at the lotus feet of the Lord. Although this is counted as karma-miśrā bhakti, or devotional service mixed with the desire to execute fruitive activities, such mixed devotional service is gradually transformed into pure devotional service. As the pious fruitive workers disengage themselves, step by step, from the bogus philosophy of “enjoyment of one’s hard-earned rewards,” pure devotional service rewards them with complete good fortune.

Śrīla Śrīdhara Svāmī has commented, ātmanā cittenāhaṅkāreṇa vā anusṛto yaḥ svabhāvas tasmāt: although one may still be in the bodily concept of life, he should offer the fruit of his work to the Supreme Personality of Godhead. Those with a primitive, materialistic concept of the Supreme Lord consider the Lord present only in a temple or church. They make some offering to the Lord in the place of worship, but in their normal activities they claim proprietorship, not thinking that God is present everywhere and within everyone. We have practical experience of many so-called religious men who become very offended if their children try to become servants of the Supreme Lord. They feel, “God should be pleased with whatever humble offering I give Him, but my family and ordinary business affairs belong to me and are under my control.” The perception of anything as separate from the Supreme Personality of Godhead or His proprietorship is called māyā, or illusion. Śrīla Śrīdhara Svāmī has quoted, na kevalaṁ vidhitaḥ kṛtam eveti niyamaḥ; svabhāvānusāri laukikam api: “The regulation that one should serve the Supreme Lord does not refer only to prescribed religious paths, ceremonies and regulations; rather, all the activities one performs in this world according to one’s personal nature should be dedicated to the Supreme Personality of Godhead.”

The words karoti yad yat sakalaṁ parasmai nārāyaṇāyeti samarpayet tat in this verse are very significant. A similar verse is found in Bhagavad-gītā (9.27):

yat karoṣi yad aśnāsi
 yaj juhoṣi dadāsi yat
yat tapasyasi kaunteya
 tat kuruṣva mad-arpaṇam

“O son of Kuntī, all that you do, all that you eat, all that you offer and give away, and all the austerities that you perform should be done as an offering unto Me.” The objection may be raised, Since our ordinary activities are performed with a material body and material mind, not by the spirit soul, how can such activities be offered to the Supreme Lord, who is completely transcendental to the material world? How can such activities be considered spiritual? In answer to this it is stated in the Viṣṇu Purāṇa (3.8.8):

varṇāśramācāra-vatā
 puruṣeṇa paraḥ pumān
viṣṇur ārādhyate panthā
 nānyat tat-toṣa-kāraṇam

One who wants to satisfy the Supreme Personality of Godhead, Viṣṇu, must accept the system of varṇāśrama-dharma and worship the Lord through the execution of his prescribed duties. In Bhagavad-gītā (4.13) the Supreme Lord has personally taken credit for establishing the system of varṇāśrama-dharma: cātur-varṇyaṁ mayā sṛṣṭaṁ guṇa-karma-vibhāgaśaḥ. Therefore if one offers his work within the varṇāśrama-dharma system to the Supreme Lord, such work is counted as devotional service. According to one’s svabhāva, or nature, one may work as an intellectual or priest, as an administrator or military man, as an agriculturist or mercantile man, or as a laborer or craftsman. And while working, everyone should meditate on the Supreme Personality of Godhead, thinking, yat sakalaṁ parasmai nārāyaṇāya: “I am working for the Supreme Lord. Whatever result comes from my work, I shall accept the bare minimum for my personal maintenance, and the rest I shall offer for the glorification of Lord Nārāyaṇa.”

Śrīla Jīva Gosvāmī has pointed out, kāmināṁ tu sarvathaiva na duṣkarmārpaṇam: one cannot offer duṣkarma, or sinful, wicked activities, to the Supreme Personality of Godhead. The four pillars of sinful life are illicit sex, meat-eating, gambling and intoxication. Such activities are never acceptable as offerings to the Supreme Personality of Godhead. The example may be given that although in a free society each person is allowed to choose his own occupation, even a democratic government will not allow a citizen to choose the occupation of thief or murderer. In the same way, according to the laws of God one is invited to work according to his own nature in the varṇāśrama system, but one is forbidden to adopt a criminal life of sinful activities violating the laws of God.

Śrīla Viśvanātha Cakravartī Ṭhākura has given a nice description of how one should offer one’s ordinary activities to the Supreme Lord. He says that an ordinary sense gratifier begins his activities in the morning by passing stool and urine, cleaning his mouth, brushing his teeth, bathing, meeting his friends and family members and discussing with them the day’s business. In this way one has so many activities during the day, and a sense gratifier executes all these activities for his personal material enjoyment. A karmī, on the other hand, working under the jurisdiction of the karma-kāṇḍa section of the Vedas, will perform the same activities for the pleasure of the demigods and his forefathers. Thus, according to Śrīla Viśvanātha Cakravartī Ṭhākura, a devotee of the Supreme Lord, Nārāyaṇa, should similarly perform all of his daily activities for the pleasure of the Supreme Lord. In this way everything we do throughout the day will become bhakty-aṅga, or a supplementary aspect of our devotional service to Kṛṣṇa.

It should be understood that as long as one identifies oneself in terms of the varṇāśrama-dharma system rather than as part and parcel of Kṛṣṇa one is still on the platform of ahaṅkāra, or false ego, because the varṇāśrama system is designed according to the modes of nature acquired by the living entity through his material body. But the ācāryas have emphasized in their commentaries on this verse that such a false ego, by which one identifies oneself as a brāhmaṇa, kṣatriya, vaiśya, śūdra, sannyāsī, gṛhastha and so on, should also be offered to the Supreme Personality of Godhead.

According to Śrīla Jīva Gosvāmī, when one becomes very much attracted to hearing and chanting about the Supreme Lord and not merely offering Him the fruits of one’s work, one has attained the stage called svarūpa-siddhā bhakti, or the stage in which actual devotion becomes visible. The example may be given that although any good citizen will pay his taxes to the government, he may not necessarily love the government or its leaders. Similarly a pious living entity can understand that he is working under the laws of God, and therefore in accordance with Vedic injunctions or the injunctions of other scriptures he offers a portion of his assets to the Supreme Lord in religious ceremonies. But when such a pious person actually becomes attached to chanting and hearing about the personal qualities of the Lord and when love thus becomes visible, he is considered to be reaching the mature stage of life. In this regard, Śrīla Jīva Gosvāmī has quoted several verses that very nicely show the development of love for Godhead. Anena durvāsanā-duḥkha-darśanena sa karuṇā-mayaḥ karuṇāṁ karotu: “May the merciful Lord show mercy on me by demonstrating the misery created by sinful desires.” Yā prītir avivekānāṁ visayeṣv anapāyinī/ tvām anusmarataḥ sā me hṛdayān nāpasarpatu: “Unintelligent persons have unflinching affection for the objects of sense gratification. Similarly, may I always remember You, so that that same attachment, applied to You, never leaves my heart.” (Viṣṇu Purāṇa 1.20.19) Yuvatīnāṁ yathā yūni yūnāṁ ca yuvatau yathā/ mano ’bhiramate tadvan mano me ramatāṁ tvayi: “As the minds of young girls take pleasure in thinking of a young boy and those of young boys take pleasure in thinking of a young girl, may my mind take pleasure in You.” Mama sukarmaṇi duṣkarmaṇi ca yad rāga-sāmānyam, tad sarvato-bhāvena bhagavad-viṣayam eva bhavatu: “Whatever attraction I have for pious or sinful activities, let that attraction be wholeheartedly invested in You.”