My two favorite quotes:
First, from Book 2 - The Lion, The Witch and the Wardrobe, p. 86
"Is--is he a man?" asked Lucy.
"Aslan a man!" said Mr. Beaver sternly. "Certainly not. I tell you he is the King of the wood and the son of the great Emperor-beyond-the-Sea. Don't you know who is the King of Beasts? Aslan is a lion--the Lion, the great Lion."
"Ooh!" said Susan, "I'd thought he was a man. Is he--quite safe? I shall feel rather nervous about meeting a lion."
"That you will, dearie, and no mistake," said Mrs. Beaver; "if there's anyone who can appear before Aslan without their knees knocking, they're either braver than most or else just silly."
"Then he isn't safe?" said Lucy.
"Safe?" said Mr. Beaver; "don't you hear what Mrs. Beaver tells you? Who said anything about safe? 'Course he isn't safe. But he's good. He's the King, I tell you."
And then the end, from Book 7 - The Last Battle, p.228
"The dream is ended: this is the morning."
And as He spoke He longer looked to them like a lion; but the things that began to happen after that were so great and beautiful that I cannot write them. And for us this is the end of all the stories, and we can most truly say that they all lived happily ever after. But for them it was only the beginning of the real story. All their life in this world and all their adventures in Narnia had only been the cover and the title page: now at last they were beginning Chapter One of the Great Story which no one on earth has read: which goes on forever: in which every chapter is better than the one before.