A pastor was walking down the street when he came upon a group of about a dozen boys, all of them between 10 and 12 years of age. The group surrounded a dog. Concerned lest the boys were hurting the dog, he went over and asked, "What are you boys doing with that dog?" 

One of the boys replied, "This dog is just an old neighborhood stray. We all want him, but only one of us can take him home. So we've decided that whichever one of us can tell the biggest lie will get to keep the dog." 

Of course the pastor was scandalized. "You boys shouldn't be having a contest telling lies!" he exclaimed. He then launched into a ten-minute sermon against lying, beginning, "Don't you boys know it's a sin to lie," and ending with, "Why, when I was your age, I never told a lie."