This is a short true to life joke that happened in Billy Graham's ministry. Prepare to laugh. Read on:
Reverend Billy Graham tells of a time early in his ministry when he arrived in a small town to preach a sermon. Wanting to mail a letter, he asked a young boy where the post office was. When the boy had told him, Dr. Graham thanked him and said, "If you'll come to the Baptist Church this evening, you can hear me telling everyone how to get to heaven."
The boy replied, "I don't think I'll be there... You don't even know your way to the post office."