Task: Question Answering
Input (English): Context: I just came across a huge find regarding the " Great Multitude " of people in Rev 7:9 . 9After this I looked and there before me was a great multitude that no one could count , from every nation , tribe , people and language , standing before the throne and in front of the Lamb . They were wearing white robes and were holding palm branches in their hands . It turns out , the same Greek phrase for " great crowd " occurs one other place , in Rev 19 , 1After this I heard what sounded like the roar of a great multitude in heaven shouting : " Hallelujah !. 
Question: What book may i be reading ?
Output (English): The bible.