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, Vrindavana 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.
Source: A.C. Bhaktivedanta Swami Prabhupada (2014 edition), “Srimad Bhagavatam”, Fourth Canto, Chapter 30 – Text 37