Here's the sermon illustration I butchered by doing it from memory in my recent sermon in the Gospel of Matthew:
In The Grace of Giving, Stephen Olford tells of a Baptist pastor during the American Revolution, Peter Miller, who lived in Ephrata, Pennsylvania, and enjoyed the friendship of George Washington. In Ephrata also lived Michael Wittman, an evil-minded sort who did all he could to oppose and humiliate the pastor. One day Michael Wittman was arrested for treason and sentenced to die. Peter Miller traveled seventy miles on foot to Philadelphia to plead for the life of the traitor.
"No, Peter," General Washington said. "I cannot grant you the life of your friend."
"My friend!" exclaimed the old preacher. "He's the bitterest enemy I have."
"What?" cried Washington. "You've walked seventy miles to save the life of an enemy? That puts the matter in different light. I'll grant your pardon." And he did.
Peter Miller took Michael Wittman back home to Ephrata--no longer an enemy but a friend. (From Lynn Jost, posted on Sermonillustrations.com)
Here's the link to the full sermon too: http://cornerstone-marion.org/sermons/11-0123_~Mercy_for_the_Merciless_~Matt_12--1-21_(Matt_Proctor).mp3
Another mistake I made is that "corn" is not a native crop in 1st Century Palestine (it's native to North America). The grain was probably barley. (Thanks Jeff for helping me get this straight.)