The strength to forestall disaster comes from Dao. The hope is to rectify people's hearts, but if they persist in doing evil, and cannot be corrected or conform to the Dao, then the only thing to do is allow the demons to bring on disaster. From the point of view of Heaven, this is tragic, but is necessary for purifying and instructing the world.
「救劫」的力量是道，希望導正人性，但若人心執拗，不能導正，和「道」無法相應的話，那也只能讓「魔」來洗劫，這就天地教化、淨化的角度來看，功用是一樣。