To start, an excerpt from CS Lewis' first fictional work, The Pilgrim's Regress: 

And now I dreamed that John went out one morning and tried to play in the road and to forget his troubles ... he went on always a few yards further till suddenly he looked up and saw that he was so far away from home that he was in a part of the road he had never seen before. Then came the sound of a musical instrument, from behind it seemed, very sweet and very short, as if it were one plucking of a string or one note of a bell, and after it, a full, clear voice - and it sounded so high and strange that he thought it was very far away, further than a star. The voice said, Come.