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 an auto.  After the purchase, they drove it home and parked 
in on the street between their establishments.  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 ran out and asked the priest what he was doing.

"I'm blessing it," the priest replied.

The rabbi considered this a moment, then said, "Oh," and ran back inside the 
synagogue.  He reappeared a moment later with a hacksaw, ran to the back of 
the car and cut off the last two inches of the tailpipe.