Here's the joke:
Once upon a time, there was an atheist college professor who dedicated his Philosophy 101 course to disproving the existence of God. Throughout the years, hundreds of students had lost their faith under his influence.
One semester, this professor was awarded a sabbatical and he decided to spend it in Wyoming. He went on a hike one day and deep within the forest he encountered a large, hungry grizzly bear. The bear came running towards him with its mouth wide open.
Just before the bear bit into him, the professor cried out: "OH MY GOD!!!!!"
Suddenly time froze. The birds stopped in midair. The long grass remained bent under a now still wind. The bear also froze with a frozen drop of saliva hanging from its teeth.
The professor heard a deep voice proclaim: "I am who I am! I am God!"
The professor answered, "Let me apologize. I have led people to disbelieve in you and now I call upon you in my hour of need. I won't be a hypocrite and ask you to save me from this bear. If you really are all powerful, I only ask that you make this bear into a devout, loving, and gracious Christian bear."
The professor heard the voice announced: "Amen!"
Suddenly time resumed. The birds began to fly again through the air. The bear suddenly closed its mouth and knelt on the ground in front of the professor.
Slowly, the bear prayed: "Bless us O Lord and these thy gifts which we are about to receive from thy bounty, through Christ our Lord. Amen."
Then the bear ate the professor.