As Johnny watched, Fr O'Reilly blessed a horse which was about to enter a race. The horse went on to win the race by miles.
Fr O'Reilly blessed five more horses, and the same thing happened each time - the horse took the lead from the beginning and led the whole way.
Johnny began to get excited. "If I put money on the next horse the old priest blesses," he thought, "it won't really be gambling, because this is a dead cert."
Once again, Johnny watched as Fr O'Reilly blessed a seventh horse. Johnny immediately went and put his savings on that horse, and watched as the race began. Sure enough, his horse took the lead from the beginning and led for most of the race - but just yards before the end, it suddenly dropped down dead.
Furious, Johnny went to confront Fr O'Reilly. "What's going on?" he shouted. "Those first six horses you blessed won by miles, so how come the seventh horse dropped down dead before the finish?"
Fr O'Reilly looked at Johnny for a moment. "You're not Catholic, are you, son?" he asked.
"What makes you say that?"
"Well, if you were, you'd know the difference between a blessing and the Last Rites."