...Borrower's don't steal."
"Except from human beings," said the boy.
Arrietty burst out laughing; she laughed so much that she had to hide her face in the primrose. "Oh dear," she gasped with tears in her eyes, "you are funny!" She stared upward at his puzzled face. "Human beans are for Borrowers - like bread's for butter!

Auteur: Mary Norton