I'll address 1 and 3 first with my thoughts as these are closely related.
Originally Posted by Forklifter
In the new testament, what is the temple of God? In Matthew, Mark and John Jesus makes this statement:
Joh 2:18 So then the Jewish leaders responded, "What sign can you show us, since you are doing these things?" Jesus replied, "Destroy this temple and in three days I will raise it up again." Then the Jewish leaders said to him, "This temple has been under construction for forty-six years, and are you going to raise it up in three days?" But Jesus was speaking about the temple of his body.
We see that the temple of God is Jesus himself. Brick and mortar are meaningless after His resurrection. Jesus also said He is greater than the temple:
Mat 12:6 I tell you that something greater than the temple is here.
Later, Paul elaborates. Jesus is the temple of God and by virtue of the Holy Spirit living within us, we are also the temple of God. Paul warns specifically against self-deception, exactly what he is doing in 2Th2.
1Co 3:16 Do you not know that you are God's temple and that God's Spirit lives in you?
1Co 3:17 If someone destroys God's temple, God will destroy him. For God's temple is holy, which is what you are.
1Co 3:18 Guard against self-deception, each of you. If someone among you thinks he is wise in this age, let him become foolish so that he can become wise.
2Co 6:16 And what mutual agreement does the temple of God have with idols? For we are the temple of the living God, just as God said, "I will live in them and will walk among them, and I will be their God, and they will be my people."
And Jesus is the cornerstone of this temple:
Eph 2:19 So then you are no longer foreigners and non-citizens, but you are fellow citizens with the saints and members of God's household, because you have been built on the foundation of the apostles and prophets, with Christ Jesus himself as the cornerstone. In him the whole building, being joined together, grows into a holy temple in the Lord, in whom you also are being built together into a dwelling place of God in the Spirit.
So we need to keep this view in mind when we look at 2Th 2:3-4 as it is critical to what we can expect as the end-times near.
2Th 2:3 Let no one deceive you in any way. For that day will not arrive until the rebellion comes and the man of lawlessness is revealed, the son of destruction.
2Th 2:4 He opposes and exalts himself above every so-called god or object of worship, and as a result he takes his seat in God's temple, displaying himself as God.
The rebellion, or the falling-away, or the apostasy, means that something else, a false Jesus, tries to take a seat in this temple – meaning to replace Christianity with a false belief system. It means Christianity itself becomes its own enemy through false doctrines. The true Jesus is replaced by a false Jesus that leads many people – who believe they are Christian – to ruin. This is why Peter speaks so much about false teachings in the very apocalyptic 2 Peter. Read all of 2 Peter Chapter 2 – it’s all about false teachings.
We see this in spades today. It is happening now. False teachings that seek to replace Christ, not destroy Christ with weapons of war and terror. To change Christ into something he’s not, in the guise of Christianity. The prosperity Gospel; Name it and Claim it; Westboro; the Emergent church; the Jesus Seminar; Christian anti-Semitism which tears at the roots of the tree we’ve been grafted in to; opulent mega-churches whose leaders worship the dollar; new age spiritualism such as what Oprah espouses that see Christ as a guru, but worship materialism or humanism; and many false beliefs.
All of these want to change Jesus into another person leading people away from truth. All of these are trying to take their place in God's temple - the very body of Christ, and display themselves as God.
“To preserve the government we must also preserve morals. Morality rests on religion; if you destroy the foundation, the superstructure must fall. When the public mind becomes vitiated and corrupt, laws are a nullity and constitutions are waste paper.” – Daniel Webster, 4th of July, 1800, Oration at Hanover, N.H.