"Here is wisdom. Let him that hath understanding count the number of the beast: for it is the number of a man; and his number IS Six hundred threescore AND six."-- Revelation 13:18
In the last part of his essay Engels explains that the purpose of the Book of Revelations (by John of Patmos) was to communicate its religious vision to the seven churches of Asia Minor and to the larger sect of Jewish Christians that they represented.
At this time, circa 69 AD, the entire Mediterranean world much of the of Near East and Western Europe were under the control of the Roman Empire. This was a multicultural empire made of hundreds of tribes, groups, cities and peoples. Within the empire was a vast underclass of workers, freedmen, slaves and peasants whose exploited labor was lived off of by a ruling class of landed aristocrats and merchants. In 69 AD the empire was in essence a military dictatorship controlled by the army and led by the Emperor (from the Latin word for "general"-- imperator).
At this time there were peoples but no nations in our sense of the word. "Nations became possible," Engels says, "only through the downfall of Roman world domination." The effects of which are still being felt in the Middle East and parts of Europe, especially eastern Europe.
For the exploited masses of the Empire it was basically impossible to resist the military power of Rome. There were uprisings and slave revolts but they were always put down by the legions. This was the background for what became a great revolutionary movement of the poor and the exploited, a movement that became Christianity. The purpose of the movement was to escape from persecution, enslavement and exploitation. A solution was offered. "But" Engels remarks, "not in this world."
Another feature of the work is that it is a symbolical representation of contemporary first century politics and John thinks that Jesus's second coming is near at hand. Jesus tells John, "Behold, I come quickly" three times (22:7, 22:12, 22:20). His failure to show up by now doesn't seem to pose a problem for Christians.
As far as the later Christian religion of love is concerned, Engels reports that you won't find it in Revelation, at least as it regards the enemies of the Christians. There is no cheek turning going on here: it's all fire and brimstone for the foes of Jesus. Engels says "undiluted revenge is preached." God is even going to completely blot out Rome from the face of the earth. He changed his mind evidently as it is still a popular tourist destination and the pope has even set up shop there.
As was pointed out earlier the God of John is Yahweh, there is no Trinity, it is He, not Christ, who will judge mankind and they wil bel judged according to their works (no justification by faith here, sorry Luther), no doctrine of original sin, no baptism, and no Eucharist or Mass. Almost everyone of these later developments came from Roman and Greek, as well as Egyptian
mystery religions. Zoroastrian elements from the Zend - Avesta are also present. These are the idea of Satan and the Devil as an evil force opposed to Yahweh, a great battle at the end of time between good and evil, [the final conflict] and the idea of a second coming. All these ideas were picked up by the Jews during their contact with the Persians before their return after the Babylonian captivity and transmitted to the early Christians.
Once we realize all this we can also see why Islam was able to rise to the status of a world religion as well. Those areas of the world that were not the home land of Greco-Roman paganism were open to Islam which spread in areas of Semitic settlement and where Christianity had been imposed by force, so could Islam be.
We will give Engels the last word, the Book of Revelation "shows without any dilution what Judaism, strongly influenced by Alexandria, contributed to Christianity. All that comes later is Western , Greco-Roman addition."