I am busy rewriting this article.
Rather read Who are the woman and her child in Revelation 12?
Why do Michael and his angels wage war in heaven against the Satan and his angels, and what weapons do they use? – A study of Revelation 12.
The dragon is identified as “the devil and Satan” (Rev 12:9):
It “stood before the woman … so that when she gave birth he might devour her child” (Rev 12:4). Ever since God told the serpent that the seed of the woman “shall bruise you on the head” (Gen 3:15), Satan stood ready to thwart Christ’s mission.
But Jesus was “caught up to God and to His throne” (Rev 12:5), meaning that Satan failed.
The dragon has seven heads and ten horns (Rev 12:3). These symbolize the kingdoms of the world (Rev 17:9-10, 12). The dragon, therefore, also represents the earthly kingdoms through which Satan persecutes God’s people.
There are three beasts in Revelation that have seven heads and ten horns each. For a more specific identification of the dragon, see – The seven-headed beasts of Revelation.
War in Heaven
The leader of God’s angels is the archangel Michael.
He and his angels are opposed by Satan and his angels, for Satan has deceived a large number of God’s beautiful angels to side with him against God.
Satan’s weapons are deception (Rev 12:9) and accusations (Rev 12:10). He deceives angels and people into sin and then accuses them before God.
This crisis in heaven, described as a “war in heaven” (Rev 12:7), is symbolized by Revelation 5 as “a book … sealed up with seven seals” which “no one in heaven … was able to open” (Rev 5:1, 3). In both chapters, the crisis is located in heaven but is solved by Christ’s death. For a further discussion, see – The seven seals verse of Revelation.
“Then another sign appeared in heaven:
and behold, a great red dragon
having seven heads and ten horns …
His tail swept away a third of the stars of heaven and threw them to the earth.
The dragon stood before the woman who was about to give birth,
so that when she gave birth he might devour her child.”
The Dragon is Satan.
Revelation 12:9 identifies the dragon as “the devil and Satan.” It “stood before the woman … so that when she gave birth he might devour her child” (Rev 12:4). Ever since God told the serpent that the seed of the woman “shall bruise you on the head” (Gen 3:15), Satan has been watching, expecting the Messiah, and standing ready to thwart His mission.
The Dragon has seven heads and ten horns
But the dragon has seven heads and ten horns, just like the beast from the sea (Rev 13:1) and the scarlet beast (Rev 17:3). “The seven heads are … seven kings” (Rev 17:9-10) and “the ten horns which you saw are ten kings” (Rev 17:12). The dragon, therefore, also represents the earthly kingdoms through which Satan persecutes God’s people. (For specific identification, see The Seven-Headed Beasts of Revelation.)
Jesus was caught up to God.
Satan stood ready to devour her child as soon as He was born (Rev 12:4), but Jesus was “caught up to God and to His throne” (Rev 12:5). In other words, Satan was defeated and Christ won the victory when He came to this earth.
War in Heaven
Rev 12:7 mentions the war in heaven briefly:
“And there was war in heaven,
Michael and his angels waging war with the dragon.
The dragon and his angels waged war.”
Michael; the archangel
It is a war between two groups of angels. The name of the leader of God’s angels is “Michael” (Rev 12:7). This name means “who is like God.” He is mentioned four times in the Bible; mostly resisting evil angels, for example:
Michael is “the archangel” and he argued with the devil “about the body of Moses” (Jude 1:9).
When Daniel saw the angel whom God sent to him, he “retained no strength” (Dan 10:8). This, therefore, was a mighty angel, but this angel was delayed for three weeks by “these forces” (Dan 10:13). “These forces,” therefore, are powerful supernatural forces. The angel said that Michael is the only one “who stands firmly with me against these forces” (Dan 10:13; cf. 12:1).
Satan and his angels
Michael and his angels wage war against Satan and his angels (Rev 12:7). This means that Satan has deceived a large number of God’s beautiful angels to his side in rebellion against God.
While verse 7 mentions the war in heaven, verses 8 to 12 describe Michael’s victory.
With what weapons are the war in heaven waged? The dragon is identified as:
“the serpent of old
who is called the devil and Satan,
who deceives the whole world” (Rev 12:9)
“the accuser of our brethren …
he who accuses them before our God day and night” (Rev 12:10).
Serpent – “The serpent … said to the woman” (Gen 3:1). The “serpent,” therefore, refers to Satan’s deception of Eve.
Satan – The name Satan means adversary (opponent). He is God’s adversary, but also of all angels and people who side with God.
Deceives – He “deceives the whole world” (Rev 12:9). Deception is one of his key strategies. In other words, to achieve his purposes, he tells lies. Jesus said of him, “Whenever he speaks a lie, he speaks from his own nature, for he is a liar and the father of lies” (John 8:44).
Accuser – He is “the accuser of our brethren:” He “accuses them before our God day and night.” Zechariah 3 shows Satan accusing Joshua the high priest of iniquity. Another example is when Satan said that Job fears God only because God protects him (Job) on all sides, but if all of Job’s possessions are taken away, then Job would curse God (Job 1:10-11).
Devil – His role as the accuser is also reflected in the name “devil” (diabolos). This Greek word means “slanderer; false accuser; unjustly criticizing to hurt (malign) and condemn.” The NASB, in a few places, also translates this word as “malicious gossips.”
Satan’s weapons, therefore, are not physical. He deceives and he accuses. See The seven seals verse of Revelation for a further discussion.