Here are my thoughts on the identity of the beast.
First of all, it is clear to me that the beast, the antichrist, and the man of sin are not the same. The antichrist is clearly identified in 1 John as the "spirit of error" and "false prophets." The Antichrist had already come when John wrote this.
1JO 4:1 Beloved, do not believe every spirit, but test the spirits, whether they are of God; because many false prophets have gone out into the world.
2 By this you know the Spirit of God: Every spirit that confesses that Jesus Christ has come in the flesh is of God,
3 and every spirit that does not confess that Jesus Christ has come in the flesh is not of God. And this is the spirit of the Antichrist, which you have heard was coming, and is now already in the world.
1JO 4:6 We are of God. He who knows God hears us; he who is not of God does not hear us. By this we know the spirit of truth and the spirit of error.
John says, "...you have heard was coming..." Jude, also mentions this. He says that they had already crept in unnoticed. (verse 4)
JUD 1:17 But you, beloved, remember the words which were spoken before by the apostles of our Lord Jesus Christ:
18 how they told you that there would be mockers in the last time who would walk according to their own ungodly lusts.
These "mockers" were called wolves by Paul.
ACT 20:29 "For I know this, that after my departure savage wolves will come in among you, not sparing the flock.
They were called false christs and false prophets by Christ.
MAT 24:24 "For false christs and false prophets will arise and show great signs and wonders, so as to deceive, if possible, even the elect."
These prophesies by Christ and the apostles were fulfilled before AD 70.
The false prophet in Revelation 19 is the same as the second beast in Revelation 13. The function of the false prophet is to get the whole world to worship the image of the first beast. The first beast is imperial Rome. Nero is the beast in the flesh at the time the Revelation was written. Imperialism was wounded by the sword with a mortal wound when the Roman republicans killed Julius. But it came back to life with Augustus. The seven heads were the first seven kings of Revelation 17. (1.) Julius (2.) Augustus (3.) Tiberius (4.) Caligula (5.) Claudius (6.) Nero (7.) Galba. The first beast comes out of the sea and is universal. The second beast comes out of the land and is nationalistic.
The second beast causes the whole world to worship the image of the first beast by saying, "We have no king but Caesar." It looks like a lamb (a symbol of priesthood), has two horns, and speaks like a dragon. One horn (power source) says, "We have no king but Caesar." The other horn says, "Give us Barabbus." It speaks like a dragon and says, "Crucify Him." This false prophet is the high priest Jewish system. This false prophet is the same as the whore of Babylon who is supported by the beast (rides the beast). She is the same as the synagogue of Satan. The father of this beast is Satan (John 8:44 "You are of your father the devil.")
JOH 19:15 But they cried out, "Away with Him, away with Him! Crucify Him!" Pilate said to them, "Shall I crucify your King?" The chief priests answered, "We have no king but Caesar!"
THE MAN OF SIN
The man of sin is proven to be John of Gischala by John Bray.
1 John of Gischala used the temple as a fort, thereby defiling it. He opened the gates to the Edomites who killed the chief priests. The high priest was the hindering force that held down the rebellion (apostacy) against Rome. Once he was taken out of the way, the man of sin was revealed, and the wrath was unleashed.THE BEAST
The only ones who participate in the first resurrection are the souls of those who have been beheaded because they refuse to take the mark of the beast. The mark of the beast has to do with participation in the temple system liturgy (see James Jordon). Jesus said, "Buy the gold that does not perish." Buying and selling in the spiritual sense has to do with worship. Since the devout Jews such as the Essenes refused to recognize the authority of the Roman supported system, they suffered outside the camp. The apostles were cast out of the synagogues. This means they could not "buy or sell" in the spiritual sense.
We who have been born again were beheaded. We have lost our former head (Adam). We were raised from the dead when we came to Christ (Eph 2:1). We are seated with Christ in heavenly places, ruling on thrones for a thousand years.
PSA 84:10 For a day in Your courts is better than a thousand.
The second resurrection comes after death. The first resurrection is when we come to Christ.
EPH 2:1 And you He made alive, who were dead in trespasses and sins,
Those who arose from the dead in Mat. 27 are simply first fruits of the second resurrection.
The beast is Imperial Rome. It is Caesar. Nero was the current beast incarnate. His name in Hebrew adds up to 666. This is because every letter in Hebrew is also a number. To take the mark of the beast is to say, "We have no king but Caesar." It is to say, "Hail Hitler." It is to build a Tower of Babel to heaven. It is to bow before the statue of Nebudchadnezzar. It is to trust the state as the highest law. There is another King! His name is Jesus.
The image of the beast is a mental image. The seal of God is a spiritual seal. We have been sealed by the Holy Spirit.
EPH 4:30 And do not grieve the Holy Spirit of God, by whom you were sealed for the day of redemption.