The great dragon: as in Rev. 12.3.

Was thrown down: the sense of the Greek verb “throw,” without a following preposition, is “was overthrown,” that is, from his place of power and prestige. At the end of the verse the Greek text says explicitly “he was thrown to the earth,” and the following clause has “and his angels were thrown with him.” In all three instances the subject of the verb in the active voice is Michael and his angels; and a language that does not use the passive voice may say this explicitly; for example, “Michael and his supporters threw that huge dragon out of heaven. He is that….”

That ancient serpent: this is a reference to the Devil as the snake in the Garden of Eden (Gen 3.1-15); Wisdom of Solomon 2.24 is the first written text we have that makes this identification: “but through the devil’s envy death entered the world…” (see also 2 Cor 11.3). The word translated serpent is in other contexts rendered “snake”; in Revelation it is used only to refer to the Devil (12.14, 15; 20.2). The word ancient does not mean primarily that the Devil is old, but that he goes back to ancient times, to the primeval days. So Translator’s New Testament and New Jerusalem Bible translate “the primeval serpent.” One may also say “that serpent (or, snake) from ancient times.”

The Devil and Satan: these are the two titles, the first one the Greek form, meaning “slanderer,” “accuser” (see 2.10), and the second one the Hebrew form, meaning “adversary,” “opponent” (see 2.9). This is not a double name, as Revised Standard Version the Devil and Satan might be understood; these are two names, “the Devil, or Satan” (Good News Translation, Revised English Bible, New Jerusalem Bible).

The deceiver of the whole world: for the verb “to deceive” see 2.20, where it is translated “to beguile.” Some languages express deceiver as “the one who makes … go astray.” Here it means to lead into sin, or into rebellion against God, by means of lies. The Greek noun for world is here specifically “the inhabited earth.” It means, of course, all the people on earth, and one may express this phrase as “that caused all the people on earth to sin.”

As both Revised Standard Version and Good News Translation show, the text says twice that the dragon was expelled from heaven, he and his angels. In some languages it will not be natural to interrupt the flow of the narrative with the identification of the dragon as the Devil, or Satan, and it may be better to translate somewhat as follows:

• The dragon and his angels were expelled from heaven. That ancient serpent, known as the Devil, or Satan, who causes everyone to sin, was thrown down to earth, together with his angels.

Or:

• Michael and his angels expelled the huge dragon and his supporters from heaven. This dragon is the serpent from ancient times, known as the Devil or Satan, who causes everyone to sin. They threw him down to earth along with all his helpers.

Quoted with permission from Bratcher, Robert G. and Hatton, Howard A. A Handbook on The Revelation to John. (UBS Handbook Series). New York: UBS, 1993. For this and other handbooks for translators see here .