From The Lion, The Witch, and the Wardrobe:

“Who said anything about safe? ‘Course he isn’t safe. But he’s good. He’s the King, I tell you.”

Wrong will be right, when Aslan comes in sight,

At the sound of his roar, sorrows will be no more,

When he bares his teeth, winter meets its death,

And when he shakes his mane, we shall have spring again.

And Aslan said nothing either to excuse Peter or to blame him but merely stood looking at him with his great unchanging eyes. And it seemed to all of them that there was nothing to be said.

“You have forgotten to clean your sword,” said Aslan.

It was true. Peter blushed when he looked at the bright blade and saw it all smeared with the Wolf’s hair and blood. He stooped down and wiped it quite clean on the grass, and then wiped it quite dry on his coat.

“Hand it to me and kneel, Son of Adam,” said Aslan. And when Peter had done so he struck him with the flat of the blade and said, “Rise up, Sir Peter Wolf’s-Bane. And, whatever happens, never forget to wipe your sword.”

The Witch was just turning away with a look of fierce joy on her face when she stopped and said,

“But how do I know this promise will be kept?”

“Haa-a-arrh!” roared Aslan, half rising from his throne; and his great mouth opened wider and the roar grew louder and louder, and the Witch, after staring for a moment with her lips wide apart, picked up her skirts and fairly ran for her life.

“Oh, children,” said the Lion, “I feel my strength coming back to me. Oh, children, catch me if you can!” He stood for a second, his eyes very bright, his limbs quivering, lashing himself with his tail…It was such a romp as no one has ever had except in Narnia; and whether it was more like playing with a thunderstorm or playing with a kitten Lucy could never make up her mind. And the funny thing was that when all three finally lay together panting in the sun, the girls no longer felt in the least tired or hungry or thirsty.

“And now,” said Aslan presently, “to business. I feel I am going to roar. You had better put your fingers in your ears.”

And they did. And Aslan stood up and when he opened his mouth to roar his face became so terrible that they did not dare to look at it. And they saw all the trees in front of him bend before the blast of his roaring as grass bends in a meadow before the wind.