Any country where people indulge in unnecessary killing of animals will have to suffer from wars and pestilence imposed by material nature
SB Canto 7
By good behavior and freedom from envy one should counteract sufferings due to other living entities, by meditation in trance one should counteract sufferings due to providence, and by practicing haṭha-yoga, prāṇāyāma and so forth one should counteract sufferings due to the body and mind. Similarly, by developing the mode of goodness, especially in regard to eating, one should conquer sleep.
By practice, one should avoid eating in such a way that other living entities will be disturbed and suffer. Since I suffer when pinched or killed by others, I should not attempt to pinch or kill any other living entity. People do not know that because of killing innocent animals they themselves will have to suffer severe reactions from material nature. Any country where people indulge in unnecessary killing of animals will have to suffer from wars and pestilence imposed by material nature. Comparing one's own suffering to the suffering of others, therefore, one should be kind to all living entities. One cannot avoid the sufferings inflicted by providence, and therefore when suffering comes one should fully absorb oneself in chanting the Hare Kṛṣṇa mantra. One can avoid sufferings from the body and mind by practicing mystic haṭha-yoga.