A passage from Tolkien’s Letter #89 to his son Christopher, 8 November 1944. Very appropriate for Easter Day.
And I concluded by saying that the Resurrection was the greatest ‘eucatastrophe’ possible in the greatest Fairy Story – and produces that essential emotion: Christian joy which produces tears because it is qualitatively like sorrow, because it comes from those places where Joy and Sorrow are at one, reconciled, as selfishness and altruism are lost in Love. Of course I do not mean that the Gospels tell what is only a fairy-story; but I do mean very strongly that they do tell a fairy-story: the greatest. Man the story-teller would have to be redeemed in a manner consonant with his nature: by a moving story. But since the author of it is the supreme Artist and the Author of Reality, this one was also made to Be, to be true on the Primary Plane. So that in the Primary Miracle (the Resurrection) and the lesser Christian miracles too though less, you have not only the sudden glimpse of the truth behind the apparent Anankê [destiny] of our world, but a glimpse that is actually a ray of light through the very chinks of the universe about us.