The scripture, written in the NT, states that the antichrist will enter the temple of God, and declare himself God. Two points that are essential to understanding this.
FIRST POINT, the temple, whatever form it takes, is God's temple. It is God's because He has chosen to dwell there. Now you think a future temple that reinstitutes animal sacrifices and the priesthood, could ever be a temple of God? Will He really dwell there? Think about that deeply and ask yourself. Does that make sense? Then ask yourself. If a future temple isn't God's, then whose is it? And if God isn't dwelling there, then where is He dwelling? In His Church. The church is the dwelling place of the Most High by virtue of the presence of the holy Spirit. The church is the temple of God in the NT.
SECOND POINT, it is true that the antichrist will present himself and declare himself as God. Anti, as in antichrist, literally means a combination of two ideas. One, the idea of opposition to God. Two, the idea of replacing Him. Replacing Jesus the Son of God, He clearly cannot even dream of replacing the Father. So he is antichrist, replacing Christ as Mediator, Redeemer, Saviour, and Lord. Sounds an unlikely scenario right? Some future individual accomplishing that in the sight of the world? And being accepted? Yet that is what scripture says. The whole world will wonder after the beast. He doesn't care about Israel. He wants the world. He wants global power, not a small nation in the middle east that requires another nation to prop it up. He wants control of every religious and political institution on the planet. And do you know, that if you understood beasts as being institutions and/or political entities, you will see the beast power has already entered the temple of God, the church, already has usurped authority and power over God's people by posing as mediator, redeemer, saviour, and sole vehicle through which to attain eternal life. And even now this beast is working full time throughout the world deceiving the church and the secular rulers into joining him in a global union of church and state. It's called ecumenism. And it is fulfilling the final few remnants of prophecy that remain before the second coming of the true Christ. That composite beast on Revelation 13 is a composite of the philosophies and traditions of those local literal OT powers of Daniel. But the beast of Revelation 13, that is a spiritual global power. No longer the literal city of Rome, but the spiritual city of Rome merging and uniting and bringing together the apostate spiritual city of Babylon.
“Come out of her, my people, that ye be not partakers of her sins, and that ye receive not of her plagues. For her sins have reached unto heaven, and God hath remembered her iniquities".