When one is engaged in devotional service, he is often surrounded by envious people, and often many enemies come to try to defeat him or stop him. This is not new in this present age, for even in the days of yore Prahlada Maharaja, who was engaged in the devotional service of the Lord, was harassed by his demoniac father, Hiranyakasipu. The atheists are always prepared to harass a devotee; therefore Caitanya Mahaprabhu suggested that one be very tolerant of these people. Nonetheless, one has to continue chanting the Hare Krsna mantra and preaching the chanting of this mantra because such preaching and chanting constitute the perfection of life.

From Srila Prabhupada’s purport to SB 4.24.67