So long we are engaged in the service of the Lord, He has assured us all protection. But if we are attacked, of course we must defend ourselves as best we can. Nobody can compare with the Merciful Nityananda. He can defend Himself quite well; He could have killed the sinners in an instant, but He had decided that He wanted to save these sinners. He was setting an example that we have to preach Krishna Consciousness even at the risk of personal violence. Just like the children sometimes become violent, but the father knows he can defend himself at any time, and so he tries to teach them correctly by reprimanding them.

From Srila Prabhupada’s letter to Karunamayi — Los Angeles 25 February, 1968