"Oh, Aslan," said she, "it was kind of you to come."
"I have been here all the time," said he, "but you have just made me visible."
"Aslan!" said Lucy almost a little reproachfully. "Don't make fun of me. As if anything I could do would make you visible!"
"It did," said Aslan. "Do you think I wouldn't obey my own rules?"
- from The Voyage of the Dawn Treader by C. S. Lewis
Lucy Pevensie had just done a very brave thing when this exchange occurred. To save the lives of her friends, she had braved the frightening upper floor of a house she had been told was haunted by a very dangerous magician (who was either alive, dead, awake, sleeping, upstairs, downstairs, or somewhere else... nobody was sure) in order to read from a specific book a magic spell which would turn invisible things visible again. She and her party, who were on a grand seafaring adventure, had been captured by some individuals who had read the reverse spell from the book and made themselves invisible. After a while they had become tired of the "invisible" gig and decided they actually did want to be visible, but they were too scared to go upstairs again because the magician had also become invisible when they read the invisibility spell. If Lucy wouldn't go upstairs, find the magic book, and read the spell, the invisible people (or whatever they were) had promised to cut the throats of Lucy and everyone with her.
Lucy went upstairs and eventually found the right spell, but when she read it, just as the invisibility spell had unintended consequences (turning the magician invisible), the visibility spell had the unintended consequence of turning anything visible that was invisible - and apparently Aslan had been hanging around those parts invisible when Lucy read the spell.
When I read this passage to my daughter a few nights ago, a few things jumped out at me. (SPOILER: in case you don't already know it because you've been hiding under a rock since 1950, Aslan is the character in the world of Narnia who is similar to Christ in our world.) The first thing is that Aslan tells Lucy that he "obeys his own rules." In the context of the story, he's saying that if there is a magic spell that is constructed based on principles that have been put into place in that world, he will not go against them. But in the context of the Christian faith of the author, the famed apologist C. S. Lewis, this idea is used to explain that evil exists in the world not because God is not powerful enough to eliminate it (He certainly is powerful enough), but because He has given mankind the option to follow or reject Him, and He will not forcefully take it back without giving mankind ample time to make our decision.
The other thing that jumped out at me was that Lucy, without knowing it, had in her hand the power to make Aslan visible to herself and to others. Think about that for a moment, knowing again that Aslan is a Christlike character. Is Lewis saying to us through story that each of us has the power to make Christ visible to others? I think that's exactly what he was saying. By simply following Christ, obeying His word to the best of our ability and relying on His grace both to help us when we are too weak to obey and to forgive us when we fail, we make Christ visible to others. Lucy was engaged in a completely selfless act when she made Aslan visible; she was scared to go upstairs, but she did it to save the lives of her friends. Although the book doesn't put it this way, if you had asked Lucy, doubtless she would have told you that she was only doing what Aslan would expect her to do. When we live our lives as we know Christ desires us to, when we begin to exhibit some of the characteristics of Jesus because we are letting Him live through us, we start to give people some idea of what Christ looks like. We make Him visible by being faithful representatives of Him on the earth.
Of course, when we make Jesus visible, we may not get to hug a lion afterward... but we may get something far better. Two words from the mouth of Jesus: "Well done."