I heard this story from my youth pastor a while ago. I'm not sure where he heard it or who the original author was, but I liked it so much I decided to write it down in my own words. I think it illustrates quite well what it means to be a Christian.
Once, long ago and in some land other than this one, there was man, a criminal, condemned to die. Well, not death, exactly, but condemned to be thrown into a pit of starving wolves, which was close enough. Law decreed that any man mighty enough to kill the wolves might have his life spared, but such a thing was yet to occur and the man knew he certainly would not be the one to do it.
When the day of his execution came, a great crowd had gathered about the wolf-pit. As he was brought forward by the guards, the man searched the faces around him for any signs of pity, but the search was futile--none would forgive him for the crimes he had commited. As he neared the edge of the pit and heard the snarling of the wolves he was filled with a great terror. Screaming aloud in desperation, he cried, "Mercy, I beg of you, mercy! Is there no man here who will help me?"
Suddenly there came a cry of "Halt!" to the guards, and the crowd jostled aside to make way for a mighty knight.
His armor was all of silver, and shone in the morning light so that he was almost too bright to look at, but his shield was white and bore no sign save a curious red cross. He was on foot.
Recognizing a personage of great importance, the condemned man kneeled. With tears streaming down his face, too far gone in despair to be ashamed, he begged the knight for one last chance at life.
The knight was silent for a long moment. When he finally spoke, his voice was quiet. "Law decrees that justice must be done for any crime," he answered.
The man bowed his head, his last hope dead.
"But it does not say who must pay for the deeds commited," the knight continued.
The man looked up again in confusion. "Surely lord," he said, "you would not require another man to take my place?"
"No," the knight said. "I will not. Such a price could not be required of one who is innocent."
The man nodded, knowing that what the knight said was true. His sentence was a fair one and only he could pay it.
"It can, however, be freely given."
The condemned man started. "Lord..." he began. "Who would--"
"I will take your place," the knight inturrupted. "For only I am strong enough to kill the wolves below."
The man was shaking his head. "No, no, lord," he mumbled. "No, it is not right, please, I have lived badly, let me at least do one thing right in dying as I deserve."
"Do you wish to die, or did you not ask me for life?"
The man was silent, torn.
"But let me say only this," the knight continued. "Such a gift does not come freely. Should I defeat the wolves in this pit, you will owe me a life-debt. This also is not something I can require of a man--you must allow me to do this for you."
The man hesitated. To spend the rest of his life indebted...perhaps the wolves were not invincible. Perhaps he could defeat them on his own. He looked over his shoulder at the pit.
Ravenous, slavering wolves growled back at him. The man shuddered.
"But should you choose to let me take your place and become my servant," the knight added, "I will give to you a purpose, a reason living, and a quest I know you can fulfill, though it will not be easy. But first you must allow me do to this thing."
The man hesitated another moment, weighed down by indecision. But another glance into the wolfpit decided him. "All right," he whispered. "I accept, my lord."
A hush fell over the crowd as the man was taken aside. Drawing his sword, the knight walked to the edge, waited but a moment, and then jumped into the pit.
The howling, yapping and snarling that filled the air made the crowd gasp in stare in fear, wondering what would become of the brave knight. But after a long while, something was thrown out of the pit. It was the bleeding carcass of the first wolf, followed soon after by a second carcass. And finally, after another long fight, the third and last carcass was thrown out of the pit. Then...nothing.
There was complete silence in the crowd for a long time. Finally, just as someone started forward to see what had become of the knight, a mailed glove came up and grasped the edge of the pit. Then slowly, bit by bit--for the crowd was too astonished to help--the knight crawled out onto the ground, weak...but alive. Then the knight took off his helmet, and only then did anyone truly recognize him--not a knight, but a prince, the Prince of all the land.
In after days the condemned man spent his life traveling about the world, telling anyone who would listen the story of his life, near death and unexpected salvation, for this was the task the Prince had placed before him. Only when he had grown too old for travel did he return to the Prince's kingdom, where he was received in honor for the faithfulness with which he had fulfilled his quest. And there he lived in peace for ever after.