Srimad Bhagavatam Canto 11, Chapter 11, Text 22

SB 11.11.22

yady aniso dharayitum
 mano brahmani niscalam
mayi sarvani karmani
 nirapeksah samacara
My dear Uddhava, if you are not able to free your mind from all material disturbance and thus absorb it completely on the spiritual platform, then perform all your activities as an offering to Me, without trying to enjoy the fruits.
If one offers one’s activities to Lord Krsna without trying to enjoy the results, one’s mind becomes purified. When the mind is purified, transcendental knowledge automatically manifests, since such knowledge is a by-product of pure consciousness. When the mind is absorbed in perfect knowledge, it can be raised to the spiritual platform, as described in Bhagavad-gita (18.54):
brahma-bhutah prasannatma
 na socati na kanksati
samah sarvesu bhutesu
 mad-bhaktim labhate param
“One who is thus transcendentally situated at once realizes the Supreme Brahman. He never laments nor desires to have anything; he is equally disposed to every living entity. In that state he attains pure devotional service unto Me.” By absorbing the mind in the transcendental form of Lord Krsna, one can surpass the stage of ordinary transcendental knowledge, by which one simply distinguishes oneself from the gross and subtle material bodies. Spiritually enriched by loving devotional service to the Lord, the mind is completely purified of all tinges of illusion. Through intense concentration on one’s relationship with the Personality of Godhead one comes to the highest standard of knowledge and becomes an intimate associate of the Personality of Godhead.
By offering one’s activities to the Personality of Godhead, one purifies one’s mind to some extent and thus comes to the preliminary stage of spiritual awareness. Yet even then one may not be able to fix one’s mind completely on the spiritual platform. At that point one should realistically assess one’s position, noting the lingering material contamination within the mind. Then, as stated in this verse, one should intensify one’s practical devotional work in the service of the Lord. If one artificially considers oneself to be supremely liberated or if one becomes casual on the path of spiritual advancement, there is serious danger of a falldown.
According to Srila Jiva Gosvami, the Lord previously explained to Uddhava jñana-misra bhakti, or devotional service mixed with the impure desire to enjoy transcendental knowledge. In this verse the Lord clearly reveals that transcendental knowledge is an automatic by-product of loving service to the Lord, and in the next verse the Lord begins His explanation of pure devotional service, which is completely sufficient for self-realization. The desire to enjoy spiritual knowledge is certainly a material desire, since the goal is one’s personal satisfaction and not the pleasure of the Supreme Lord. Therefore Lord Krsna here warns Uddhava that if one is not able to fix one’s mind in trance on the spiritual platform, then one should not go on simply theoretically discussing what is Brahman and what is not Brahman. Rather, one should engage in practical devotional service to the Supreme Lord, and then spiritual knowledge will automatically awaken in one’s heart. As stated in Bhagavad-gita (10.10):
tesam satata-yuktanam
 bhajatam priti-purvakam
dadami buddhi-yogam tam
 yena mam upayanti te
“To those who are constantly devoted and worship Me with love, I give the understanding by which they can come to Me.”
Similarly, in the Tenth Canto of Srimad-Bhagavatam Lord Brahma warns that one should not neglect the auspicious path of bhakti and instead take up the useless labor of mental speculation. By mere philosophical speculation one cannot fix one’s mind on the spiritual platform. Many great philosophers throughout history had abominable personal habits, which proves that they could not fix themselves on the spiritual platform by mere speculation on philosophical categories. If one is not fortunate enough to have executed devotional service to the Lord in one’s past life, and if one is therefore addicted to mere speculation on the differences between matter and spirit, one will not be able to fix one’s mind on the spiritual platform. Such a person should give up useless speculation and engage in the practical work of Krsna consciousness, absorbing himself twenty-four hours a day in the mission of the Supreme Personality of Godhead. In such missionary work for the Lord’s sake, one should never try to enjoy the fruits of one’s work. Even though the mind is not completely pure, if one offers the fruits of one’s work to the Lord, the mind will quickly come to the standard of pure desirelessness, in which one’s only desire is the Lord’s satisfaction.
Srila Jiva Gosvami states that if one does not have faith in the personal form and activities of the Personality of Godhead, one will not have the spiritual strength to remain perpetually on the transcendental platform. In this verse the Lord is definitely bringing Uddhava, and all living entities, to the conclusion of all philosophy — pure devotional service to the Supreme Lord, Krsna.
In this regard, Srila Bhaktisiddhanta Sarasvati Thakura points out that one who is bewildered by false ego may not want to offer his activities to the Supreme Personality of Godhead, even though this is the actual way of rising above the influence of the modes of material nature. Because of ignorance one does not know that he is the eternal servant of Krsna and instead is attracted by the duality of material illusion. One cannot become free from such illusion by theoretical speculation, but if one offers one’s work to the Personality of Godhead, one will clearly understand his eternal, transcendental position as a servant of the Lord.
Srimad Bhagavatam Canto 11, Chapter 11, Text 21
Srimad Bhagavatam Canto 11, Chapter 11, Text 23-24