You will need a Bible to figure out this riddle — rather, this joke. It is pretty funny.
A new pastor was visiting in the homes of his parishioners. At one house it seemed obvious that someone was at home, but no answer came to his repeated knocks at the door. Therefore, he took out his business card and on the back he wrote "Revelation 3:20." Then he slipped it under the door.
When the offering was processed the following Sunday, he found that his business card had been returned in the offering basket. Written under his note "Revelation 3:20" was a cryptic message. It read "Genesis 3:10."
Reaching for his Bible to check out the citation, he broke up in gales of laughter. Why?
By the way, you can do Bible searches from my home page so you don't have to run and get a Bible :-)