For people who had ever had the thought that free will came at too large a price, God had made a miscalculation in the creation of man or we would be happier without the possibility of sin.
C.S Lewis wrote,
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. He 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 than 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 war in the universe a price worth paying for free will — that is, for making 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 it is worth paying.
How do we reason with the person who gave us reason?