The_Complete_Chronicles_of_Narnia_(volumes_1-7,_in_order_of_publication)

Everyone in that crowd turned its head, and then everyone drew a long breath of wonder
and delight. A little way off, towering over their heads, they saw a tree which had
certainly not been there before. It must have grown up silently, yet swiftly as a flag rises
when you pull it up on a flagstaff, while they were all busied about the coronation. Its
spreading branches seemed to cast a light rather than a shade, and silver apples peeped
out like stars from under every leaf. But it was the smell which came from it, even more
than the sight, that had made everyone draw in their breath. For a moment one could
hardly think about anything else.
"Son of Adam," said Aslan, "you have sown well. And you, Narnians, let it be your first
care to guard this Tree, for it is your Shield. The Witch of whom I told you has fled far
away into the North of the world; she will live on there, growing stronger in dark Magic.
But while that Tree flourishes she will never come down into Narnia. She dare not come
within a hundred miles of the Tree, for its smell, which is joy and life and health to you,
is death and horror and despair to her."
Everyone was staring solemnly at the Tree when Aslan suddenly swung round his head
(scattering golden gleams of light from his mane as he did so) and fixed his large eyes on
the children. "What is it, children?" he said, for he caught them in the very act of
whispering and nudging one another.
"Oh - Aslan, sir," said Digory, turning red, "I forgot to tell you. The Witch has already
eaten one of those apples, one of the same kind that Tree grew from." He hadn't really
said all he was thinking, but Polly at once said it for him (Digory was always much more
afraid than she of looking a fool.)
"So we thought, Aslan," she said, "that there must be some mistake, and she can't really
mind the smell of those apples."
"Why do you think that, Daughter of Eve?" asked the Lion. '
"Well, she ate one."
"Child," he replied, "that is why all the rest are now a horror to her. That is what happens
to those who pluck and eat fruits at the wrong time and in the wrong way. The fruit is
good, but they loathe it ever after."
"Oh I see," said Polly. "And I suppose because she took it in the wrong way it won't work
for her. I mean it won't make her always young and all that?"
"Alas," said Aslan, shaking his head. "It will. Things always work according to their
nature. She has won her heart's desire; she has unwearying strength and endless days like
a goddess. But length of days with an evil heart is only length of misery and already she
begins to know it. All get what they want; they do not always like it."