The jws wrote all the stuff they wrote because they thought that the tribulation started in 1914. But the fact is the book of revelations and many things written in the NT was a repeat of what was written in the old testament. Even the apocalyptic nature of Revelations was a throw back to what was written in some of the minor prophets books like Zechariah i believe.
But thats not all, they idea that ones spirit would be gathered in heaven people would be judged on thier heart conditions and then the survivers would come back to earth is all taken from the Egyptian book if the dead. Jesus battling a dragon and all the symbology with beast and men that are half scorpions is all a throw back to the Babylonian and Sumerian religious writings. In the end the bible is a compulation of religious writings from Persia, Babylon, Assyria, Egypt and Greece.