I'm not sure who originated this joke but it's something I've heard in college and now I'm repeating it here.
A man was on his way to the Grand Canyon but his car died on the way near a farm. So, he knocked on the
door of the family there and asked to borrow their car to go to the Grand Canyon.
"We don't have a car but we have a mule that you can use if you want to," they told him.
That's better than walking, the man felt. So, he decided to take it.
"But we raised it here and it only understands two words," the family warned him. "'Amen' means go and 'Hallelujah' means stop."
The man hopped onto the back of the mule and said "Amen" and the mule started moving forward. "Hallelujah" and it stopped.
So, one "Amen" after another made the mule gallop quite fast. Soon, they reached the Grand Canyon and came upon a cliff.
"Stop! Stop! Stop!" the man yelled.
The mule showed no sign of stopping and kept heading towards the cliff.
As is natural for animal instincts of dangers and other basic things, however, the mule slowly halted right at the edge of the cliff.
Wiping off his sweat over his forehead, the man said "Wheeew! Amen!"