A priest and a rabbi operated a church and a synagogue across the street from each other. Since their schedules intertwined, they decided to go in together to buy a car. After the purchase, they drove it home and parked it on the street between them.
A few minutes later, the rabbi looked out and saw the priest sprinkling water on their new car. It didn't need a wash, so he hurried out and asked the priest what he was doing. "I'm blessing it," the priest replied.
The rabbi considered this a moment, then went back inside the synagogue. He reappeared a moment later with a hacksaw, walked over to the back of the car and cut off two inches of the tailpipe.