In his original preface written from Magdalen College at Oxford on July 5, 1941, Lewis warned of what he called “the two equal and opposite errors into which our race can fall about the devils.” One error “is to disbelieve in their existence. The other is to believe and to feel an excessive and unhealthy interest in them.” Lewis concluded that the devils “are equally pleased by both errors, and hail a materialist or a magician with the same delight.”
Lewis noted the failures born from mankind’s fallen nature. But he believed in the power of Jesus Christ to overcome sin, death and Satan, and the optimism of faith and hope.
“The Screwtape Letters” concludes by echoing the words of the First Epistle of John, as the patient dies in a bombing raid and goes to heaven””seeing not only angels but Christ himself. For as St. John declared, “I write these things to you who believe in the name of the Son of God so that you may know that you have eternal life. . . . The one who was born of God keeps him safe, and the evil one cannot harm him.”