C.S. Lewis has a nice little essay called, "The Efficacy of Prayer" which I remembered after writing the last post. Its more about how you can tell if prayer really "works" but he then moves into the subject I'm thinking about now. He answers with a quote from Pascal:
"God", said Pascal, "instituted prayer in order to lend to His creatures the dignity of causality." (Lewis continues) But not only prayer; whenever we act at all He lends us that dignity. It is not really stranger, nor less strange, that my prayers should affect the course of events than that my other actions should do so. They have not advised or changed God's mind - that is, His over-all purpose. But that purpose will be realized in different ways according to the actions, including prayers, of His creatures.
In a universe ruled by an omnipotent God do any of our actions actually accomplish anything or are we just puppets, playing out the irresistible will of God. As Christians we believe that is not the case, that we have free will and that our actions have meaning and consequences. Why should prayer not simply be one more action we may take to affect our world?
Prayer only being effective when it is in line with God's will makes more sense in this light. We know that our actions in life will, more often than not, be futile unless they are founded in God's will. Prayer, as a way of affecting ourselves and the world around us, is only effective when it is based in God's will. And, as with other actions outside of God's will, if a prayer outside of His will is granted, beware, it is to your hurt and only His grace will bring you back to safety in faith.