A living being cannot be vacant of desires. He is not a dead stone. He must be working, thinking, feeling and willing. But when he thinks, feels and wills materially, he becomes entangled, and conversely when he thinks, feels and wills for the service of the Lord, he becomes gradually freed from all entanglement. The more a person is engaged in the transcendental loving service of the Lord, the more he acquires a hankering for it. That is the transcendental nature of godly service. Material service has satiation, whereas spiritual service of the Lord has neither satiation nor end. One can go on increasing his hankerings for the loving transcendental service of the Lord, and yet he will not find satiation or end. By intense service of the Lord, one can experience the presence of the Lord transcendentally. Therefore seeing the Lord means being engaged in His service because His service and His person are identical. The sincere devotee should go on with sincere service of the Lord. The Lord will give proper direction as to how and where it has to be done. There was no material desire in Nārada, and yet just to increase his intense desire for the Lord, he was so advised.
(Srimad Bhagavatam----1:6:22----purport).

As the Lord says in Bhagavad-gītā (18.68-69):
ya idaṁ paramaṁ guhyaṁ
mad-bhakteṣv abhidhāsyati
bhaktiṁ mayi parāṁ kṛtvā
mām evaiṣyaty asaṁśayaḥ
na ca tasmān manuṣyeṣu
kaścin me priya-kṛttamaḥ
bhavitā na ca me tasmād
anyaḥ priyataro bhuvi
"For one who explains the supreme secret to the devotees, devotional service is guaranteed, and at the end he will come back to Me. There is no servant in this world more dear to Me than he, nor will there ever be one more dear." Let us continue preaching the message of Lord Kṛṣṇa and not be afraid of enemies. Our only duty is to satisfy the Lord by this preaching, which will be accepted as service by Lord Caitanya and Lord Kṛṣṇa. We must sincerely serve the Lord and not be deterred by so-called enemies.
(Srimad Bhagavatam----6:5:39----purport).

The florist very humbly and submissively offered his prayers to the Lord, saying, "My dear Lord, because You have come to my place, I think all my forefathers and all my worshipable superiors are pleased and delivered. My dear Lord, You are the supreme cause of all causes of this cosmic manifestation, but for the benefit of the residents of this earthly planet, You have appeared with Your plenary portion to give protection to Your devotees and annihilate the demons. You are equally disposed as the friend of all living entities; You are the Supersoul, and You do not discriminate between friend and enemy. Yet You are pleased to give Your devotees the special result of their devotional activities. My Lord, I am praying that You please tell me whatever You wish me to do, because I am Your eternal servant. If You would order me to do something, it would be a great favor to me." The florist, Sudāmā, was greatly pleased within his heart by seeing Kṛṣṇa and Balarāma in his place, and thus, as his choicest desire, he made two exquisite garlands of various flowers and presented them to the Lord. Kṛṣṇa and Balarāma were very much pleased with his sincere service, and Kṛṣṇa offered the florist His salutation and benedictions, which He is always prepared to bestow upon the surrendered souls. When the florist was offered benedictions, he begged from the Lord that he might remain His eternal servant in devotional service and by such service do good to all living creatures. By this, it is clear that a devotee of the Lord in Kṛṣṇa consciousness should not be satisfied simply by his own advancement in devotional service; he must be willing to work for the welfare of all others. This example was followed by the six Gosvāmīs of Vṛndāvana. It is therefore stated in a prayer about them, lokānāṁ hita-kāriṇau: Vaiṣṇavas, or devotees of the Lord, are not selfish. Whatever benefits they derive from the Supreme Personality of Godhead as benedictions they want to distribute to all other persons. That is the greatest of all humanitarian activities. Being satisfied with the florist, Lord Kṛṣṇa not only gave him whatever benedictions he wanted, but over and above that He offered him all material opulences, family prosperity, a long duration of life and whatever else his heart desired within the material world.
(Krsna Book).

Material contamination is so strong that everyone is working very hard day and night for material happiness. The show of religion, austerity, penance, humanitarianism, philanthropy, politics, science—everything is aimed at realizing some material benefit. For the immediate success of material benefit, materialistic persons generally worship different demigods, and under the spell of material propensities they sometimes take to the devotional service of the Lord. But sometimes it so happens that if a person sincerely serves the Lord and at the same time maintains material ambitions, the Lord very kindly removes the sources of material happiness. Not finding any recourse in material happiness, the devotee then engages himself absolutely in pure devotional service.
(Krsna Book).

Yet any service rendered to the Supreme Personality of Godhead is never lost: svalpam apy asya dharmasya trāyate mahato bhayāt (BG 2.40). A little devotional service rendered sincerely is a permanent asset.
(Srimad Bhagavatam----5:14:43----purport).