…In the Śrīmad Bhagavad-gītā the Lord asserts that He appears in every millennium just to reestablish the way of religion. The way of religion is made by the Supreme Lord. No one can manufacture a new path of religion, as is the fashion for certain ambitious persons. The factual way of religion is to accept the Lord as the supreme authority and thus render service unto Him in spontaneous love.
The Lord, however, out of His causeless mercy, because He is more merciful to the suffering living beings than they can expect, appears before them and renovates the principles of devotional service comprised of hearing, chanting, remembering, serving, worshiping, praying, cooperating and surrendering unto Him. Adoption of all the above-mentioned items, or any one of them, can help a conditioned soul get out of the tangle of nescience and thus become liberated from all material sufferings created by the living being illusioned by the external energy. This particular type of mercy is bestowed upon the living being by the Lord in the form of Lord Śrī Caitanya Mahāprabhu. (from Purport to SB 1.8.35)
Full Text and puroprt More
The Hare Krishna Movement 