"The Price of Free Will
Christians, then, believe that an evil power has made himself for the present the Prince of this World. And, of course, that raises problems. Is this state of affairs in accordance with God's will or not? If it is, He is a strange God, you will say: and if it is not, how can anything happen contrary to the will of a being with absolute power...
God created things which had free will. That means creatures which can go either wrong or right. Some people think they can imagine a creature which was free but had no possibility of going wrong; I cannot. If a thing is free to be good it is also free to be bad...Of course God knew what would happen if they used their freedom the wrong way; apparently He thought it worth the risk. Perhaps we feel inclined to disagree with Him. But there is a difficulty about disagreeing with God. His is the source from which all your reasoning power comes: you could not be right and He wrong any more than a stream can rise higher from its own source. When you are arguing against Him you are arguing against the very power that makes you able to argue at all: it is like cutting off the branch you are sitting on. If God thinks this state of wat in the universe a price worth paying for free will - that is, for makingl a live world in which creatures can do real good or harm and something of real importance can happen, instead of a toy world which only moves when He pulls the strings - then we may take it worth paying. "
-From Mere Christianity Bk. 2 Chap 3