Indy picked up the old Bible and inspected it. It was extremely old and worn, its pages showed user wear over time. This book has been read through many times, and has seen better days. He opened up the front of the old Bible and read an old signature. "By God.." He gasped. His face lit up with excitement as he realized the significance of the artifact he was holding. "This is no ordinary Bible. This is George Washington's Bible!" He pointed at Washington's signature, then noticed the marker placement. "It has a passage marked in the Book of Revelations..." He opened the holy book to the passage that was marked. 

“And there before me stood a white horse, and it’s rider held a bow. And his name was Death. And then a voice like thunder said, ‘Come and see!’” 

Indiana Jones has done much of his research with ancient texts to include and extensive knowledge of the Old and New Testaments of the Jewish-Christian scriptures. "This tells of the four horsemen of the Apocalypse."