These are some of the ways in which the Supreme Personality of Godhead can be satisfied by the devotee. The first item mentioned is dayayā sarva-bhūteṣu, showing mercy to all conditioned souls. The best way to show mercy is to spread Kṛṣṇa consciousness. The entire world is suffering for want of this knowledge. People should know that the Supreme Personality of Godhead is the original cause of everything. Knowing this, everyone should directly engage in His devotional service. Those who are actually learned, advanced in spiritual understanding, should preach Kṛṣṇa consciousness all over the world so that people may take to it and make their lives successful.
(Srimad Bhagavatam----4:31:19----purport).

This is a true description of a brāhmaṇa. A brāhmaṇa is one who has assimilated the Vedic conclusions by practicing mind and sense control. He speaks the true version of all the Vedas. As confirmed in the Bhagavad-gītā (15.15): vedaiś ca sarvair aham eva vedyaḥ. By studying all the Vedas, one should come to understand the transcendental position of Lord Śrī Kṛṣṇa. One who actually assimilated the essence of the Vedas can preach the truth. He is compassionate to conditioned souls who are suffering the threefold miseries of this conditional world due to their not being Kṛṣṇa conscious. A brāhmaṇa should take pity on the people and preach Kṛṣṇa consciousness in order to elevate them. Śrī Kṛṣṇa Himself, the Supreme Personality of Godhead, personally descends into this universe from the spiritual kingdom to teach conditioned souls about the values of spiritual life. He tries to induce them to surrender unto Him. Similarly, the brāhmaṇas do the same thing. After assimilating the Vedic instructions, they assist the Supreme Lord in His endeavor to deliver conditioned souls. The brāhmaṇas are very dear to the Supreme Lord due to their high sattva-guṇa qualities, and they also engage in welfare activities for all conditioned souls in the material world.
(Srimad Bhagavatam----5:5:24----purport).

O Supreme Personality of Godhead, O Nārāyaṇa, O Vāsudeva, original person! O most exalted person, supreme experience, welfare personified! O supreme benediction, supremely merciful and changeless! O support of the cosmic manifestation, sole proprietor of all planetary systems, master of everything and husband of the goddess of fortune! Your Lordship is realized by the topmost sannyāsīs, who wander about the world to preach Kṛṣṇa consciousness, fully absorbed in samādhi through bhakti-yoga. Because their minds are concentrated upon You, they can receive the conception of Your personality in their fully purified hearts. When the darkness in their hearts is completely eradicated and You are revealed to them, the transcendental bliss they enjoy is the transcendental form of Your Lordship. No one but such persons can realize You. Therefore we simply offer You our respectful obeisances."
(Srimad Bhagavatam----6:9:33----purport).

"One can understand the Supreme Personality as He is only by devotional service." Prahlāda Mahārāja ultimately instructed his class friends, the sons of the demons, to accept the process of devotional service by preaching the science of Kṛṣṇa consciousness to everyone. Preaching is the best service to the Lord. The Lord will immediately be extremely satisfied with one who engages in this service of preaching Kṛṣṇa consciousness. This is confirmed by the Lord Himself in Bhagavad-gītā (18.69). Na ca tasmān manuṣyeṣu kaścin me priya-kṛttamaḥ: "There is no servant in this world more dear to Me than he, nor will there ever be one more dear." If one sincerely tries his best to spread Kṛṣṇa consciousness by preaching the glories of the Lord and His supremacy, even if he is imperfectly educated, he becomes the dearmost servant of the Supreme Personality of Godhead. This is bhakti. As one performs this service for humanity, without discrimination between friends and enemies, the Lord becomes satisfied, and the mission of one's life is fulfilled. Śrī Caitanya Mahāprabhu therefore advised everyone to become a guru-devotee and preach Kṛṣṇa consciousness (yāre dekha, tāre kaha 'kṛṣṇa'-upadeśa (CC.2:7:128). That is the easiest way to realize the Supreme Personality of Godhead.
(Srimad Bhagavatam----7:6:24----purport).

The word ātmaupamyena refers to thinking others to be like oneself. One can very intelligently conclude that without devotional service, without becoming Kṛṣṇa conscious, one cannot be happy. Therefore the duty of all devotees is to preach Kṛṣṇa consciousness everywhere all over the world, because all living entities without Kṛṣṇa consciousness are suffering the pangs of material existence. To preach Kṛṣṇa consciousness is the best welfare activity. Indeed, it is described by Śrī Caitanya Mahāprabhu as para-upakāra, work for the true benefit of others. The activities of para-upakāra have been especially entrusted to those who have taken birth in India as human beings.
(Srimad Bhagavatam----7:7:53----purport).

In the Bhagavad-gītā, Eighteenth Chapter, the Lord states that one who is engaged in preaching Kṛṣṇa consciousness is very dear to Him. A preacher has to face many difficulties in his struggle to preach pure Kṛṣṇa consciousness. Sometimes he has to suffer bodily injuries, and sometimes he has to meet death also. All this is taken as a great austerity on behalf of Kṛṣṇa. Kṛṣṇa therefore has said that such a preacher is very, very dear to Him. If Kṛṣṇa's enemies can expect salvation simply by concentrating their minds on Him, then what to speak of persons who are so dear to Kṛṣṇa? The conclusion should be that the salvation of those who are engaged in preaching Kṛṣṇa consciousness in the world is guaranteed in all circumstances. But such preachers never care for salvation, because factually one who is engaged in Kṛṣṇa consciousness, devotional service, has already achieved salvation.
(Krsna Book).

The devotees of Lord Caitanya must preach Kṛṣṇa consciousness in every village and town in the world. That will satisfy the Lord. It is not that one should act whimsically for his own personal satisfaction. This order comes down through the paramparā system, and the spiritual master presents these orders to the disciple so that he can spread the message of Śrī Caitanya Mahāprabhu. It is the duty of every disciple to carry out the order of the bona fide spiritual master and spread Lord Caitanya's message all over the world.
(Sri Caitanya Caritamrta-----2:16:64----purport).