Kṛṣṇa-kathā is the only remedy for all people of the world because it can situate one in pure consciousness of the self and liberate one from material bondage. To preach kṛṣṇa-kathā all over the world, as recommended by Lord Caitanya, is the greatest missionary activity, and all sensible men and women of the world may join in this great movement started by Lord Caitanya.
-Shrimad Bhagvatam Canto 3 Chapter 5 Verse 11, Translation and Purport

नेहाभिक्रमनाशोऽस्ति प्रत्यवायो न विद्यते ।
स्वल्पमप्यस्य धर्मस्य त्रायते महतो भयात् ॥ ४० ॥
In this endeavor there is no loss or diminution, and a little advancement on this path can protect one from the most dangerous type of fear.
-Bhagavad-Gita Chapter 2 Verse 40