The_Complete_Chronicles_of_Narnia_(volumes_1-7,_in_order_of_publication)

"I - I nearly ate one myself, Aslan," said Digory. "Would I -"
"You would, child," said Aslan. "For the fruit always works - it must work - but it does
not work happily for any who pluck it at their own will. If any Narnian, unbidden, had
stolen an apple and planted it here to protect Narnia, it would have protected Narnia. But
it would have done so by making Narnia into another strong and cruel empire like Charn,
not the kindly land I mean it to be. And the Witch tempted you to do another thing, my
son, did she not?"
"Yes, Aslan. She wanted me to take an apple home to Mother."
"Understand, then, that it would have healed her; but not to your joy or hers. The day
would have come when both you and she would have looked back and said it would have
been better to die in that illness."
And Digory could say nothing, for tears choked him and he gave up all hopes of saving
his Mother's life; but at the same time he knew that the Lion knew what would have
happened, and that there might be things more terrible even than losing someone you
love by death. But now Aslan was speaking again, almost in a whisper:
"That is what would have happened, child, with a stolen apple. It is not what will happen
now. What I give you now will bring joy. It will not, in your world, give endless life, but
it will heal. Go. Pluck her an apple from the Tree."
For a second Digory could hardly understand. It was as if the whole world had turned
inside out and upside down. And then, like someone in a dream, he was walking across to
the Tree, and the King and Queen were cheering him and all the creatures were cheering
too. He plucked the apple and put it in his pocket. Then he came back to Aslan.
"Please," he said, "may we go home now?" He had forgotten to say "Thank you", but he
meant it, and Aslan understood.
CHAPTER FIFTEEN
THE END OF THIS STORY AND THE BEGINNING OF ALL THE OTHERS
"You need no rings when I am with you," said the voice of Aslan. The children blinked
and looked about them. They were once more in the Wood between the Worlds; Uncle
Andrew lay on the grass, still asleep; Aslan stood beside them.
"Come," said Aslan; "it is time that you went back. But there are two things to see to first;
a warning, and a command. Look here, children."