Srimad Bhagavatam Canto 04, Chapter 30, Text 37

SB 4.30.37

tesam vicaratam padbhyam
 tirthanam pavanecchaya
bhitasya kim na roceta
 tavakanam samagamah
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
Dear Lord, Your personal associates, devotees, wander all over the world to purify even the holy places of pilgrimage. Is not such activity pleasing to those who are actually afraid of material existence?
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
There are two kinds of devotees: one is called gosthyanandi and the other bhajananandi. The word bhajananandi refers to the devotee who does not move, but remains in one place. Such a devotee is always engaged in the devotional service of the Lord. He chants the maha-mantra as taught by many acaryas and sometimes goes out for preaching work. The gosthyanandi is one who desires to increase the number of devotees all over the world. He travels all over the world just to purify the world and the people residing in it. Caitanya Mahaprabhu advised:
prthivite ache yata nagaradi grama
 sarvatra pracara haibe mora nama
Lord Caitanya Mahaprabhu wanted His followers to move all over the world to preach in every town and village. In the Caitanya sampradaya, those who strictly follow the principles of Lord Caitanya must travel all over the world to preach the message of Lord Caitanya, which is the same as preaching the words of Krsna — Bhagavad-gita — and Srimad-Bhagavatam. The more the devotees preach the principles of krsna-katha, the more people throughout the world will benefit.
Devotees like the great sage Narada, who travel all over to preach, are called gosthyanandi. Narada Muni is always wandering throughout the universe just to create different types of devotees. Narada even made a hunter a devotee. He also made Dhruva Maharaja and Prahlada devotees. Actually, all devotees are indebted to the great sage Narada, for he has wandered both in heaven and in hell. A devotee of the Lord is not even afraid of hell. He goes to preach the glories of the Lord everywhere — even in hell — because there is no distinction between heaven and hell for a devotee:
narayana-parah sarve
 na kutascana bibhyati
 api tulyartha-darsinah
“A pure devotee of Narayana is never afraid of going anywhere and everywhere. For him heaven and hell are one and the same.” (Bhag. 6.17.28) Such devotees, wandering all over the world, deliver those who are actually afraid of this material existence. Some people are already disgusted with material existence, being confused and frustrated by material enjoyment, and some people, who are intelligent, are interested in understanding the Supreme Lord. Both may take advantage of the pure devotee who wanders throughout the world.
When a pure devotee goes to a place of pilgrimage, he desires to purify that holy place of pilgrimage. Many sinful men bathe in the holy waters of the places of pilgrimage. They take their baths in the waters of the Ganges and Yamuna at places such as Prayaga, Vrndavana and Mathura. In this way the sinful men are purified, but their sinful actions and reactions remain at the holy places of pilgrimage. When a devotee comes to take his bath at those places of pilgrimage, the sinful reactions left by the sinful men are neutralized by the devotee. Tirthi-kurvanti tirthani svantah-sthena gada-bhrta (Bhag. 1.13.10): because the devotee always carries the Supreme Personality of Godhead within his heart, wherever he goes becomes a place of pilgrimage, a holy place for understanding the Supreme Personality of Godhead. It is therefore the duty of everyone to associate with a pure devotee and thus attain freedom from material contamination. Everyone should take advantage of the wandering devotees, whose only business is to deliver conditioned souls from the clutches of maya.
Srimad Bhagavatam Canto 04, Chapter 30, Text 36
Srimad Bhagavatam Canto 04, Chapter 30, Text 38