The duty of all devotees is to preach Krsna consciousness everywhere all over the world, because all living entities without Krsna consciousness are suffering the pangs of material existence

Expressions researched:
"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"

Srimad-Bhagavatam

SB Canto 7

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.

SB 7.7.53, Translation and Purport

My dear friends, O sons of the demons, in the same favorable way that one sees himself and takes care of himself, take to devotional service to satisfy the Supreme Personality of Godhead, who is present everywhere as the Supersoul of all living entities.

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.

bhārata-bhūmite haila manuṣya-janma yāra

janma sārthaka kari' kara para-upakāra

(CC Adi 9.41)

The entire world is suffering for want of Kṛṣṇa consciousness. Therefore Śrī Caitanya Mahāprabhu advised all human beings born in India to make their lives perfect by Kṛṣṇa consciousness and then preach the gospel of Kṛṣṇa consciousness all over the world so that others may become happy by executing the principles of Kṛṣṇa consciousness.