1. Actual mercy to all living entities

    The devotee can do good not only to humanity but to all living entities as well. Everyone can benefit spiritually by the chanting of the Hare Krsna maha-mantra. When the transcendental vibration of Hare Krsna is sounded, even the trees, animals and insects benefit. Thus when one chants the Hare Krsna maha-mantra loudly, he actually shows mercy to all living entities.

    From Srila Prabhupada’s purport to SB 4.31.19