Aslan gave his life for Edmand’s because he knew of a secret that the Witch did not that made death not so horrible. After the meeting with the Witch, he seemed sad and very distracted. “Well what about the secret he knew? You just said it would make everything better?” you may ask. I did, but the road to the glorious victory is sad. Aslan knew that he would have to die, and he even knew how; by means of Stone Table persecution, the most horrible death. He thought of all the things they would do to him and how he would have to endure the pain and not fight back! They spat on him, they smote him, they bound him so tightly it pierced his very skin, and they shaved him revealing a more solemn appearance that made them not fear him anymore. Through all the pain and persecution, he knew that it would only last for a season and that the deeper magic unknown to the Witch would come to pass by the next morning. The deepest magic of all stated that when an innocent creature was killed on the Stone Table in place of a traitor, the Stone Table would crack and death itself could not be stopped by the Witch; and it did and Aslan was back and as strong and ready as ever to defeat the Witch.
Chronicles of Narnia 5
November 13, 2010