There is one excellent argument for the non-existence of a benevolent, omniscient, omnipotent God. It is known as theodicy. People suffer in this world for no apparent reason. Such living things as parasites exist to increase that suffering. If God made all life, then he finds the malarial parasite as important as the human being. Bart Ehrman just wrote a book, God's Problem. It is indeed a problem if we are to assume the existence of a loving God.