Problems With Petitionary Prayer
Petitionary prayer is a fundamental element of Christian practice. It is taught by the Church, and it is taught by the Bible; it is uncontroversial: Christians ought to pray. Indeed, one would probably feel inclined to question the rationality of anyone who believed that there is an omnipotent deity on his side, and yet did not request assistance from that deity in times of need. How petitionary prayer is supposed to work, though, is difficult to say. Arguably, this fundamental element of Christianity doesn‘t make sense.
There is certainly something very strange about the idea of God changing his mind. As God is omniscient, every decision that he makes he makes in light of all of the facts; there cannot arise any new information that God failed to take into account that might cause him to revise his decision. God, then, should never change his mind.
This means that telling God of our needs and asking him to meet them is a waste of time; God is fully aware both of our needs and of our desires, and will have taken them into account in making his original decision. Whatever decision he has made, whether it is in our favour or not, we should not question; our judgement as to what God should do will surely be inferior to his, and so we should let him get on with doing what he is going to do.
It therefore seems that Christians ought not to pray petitionary prayers. Prayers of worship and adoration are understandable, of course, but requests for divine intervention seem to be futile; whatever God is going to do he will do, whatever he is not he will not. Our prayers won‘t change that.