Of course one could possibly spiritualise the whole thing and believe that the Antichrist spirit will enter completely into the Church itself , or maybe an individual Christian(i.e. a "temple of God"), or one who seems to be a Christian, in a similar way that it says Satan entered into Judas, who was one of the Twelve, and probably did miracles, and certainly preached in the name of Jesus.
Please allow me to discuss 2 Thessalonians 2:1-7 for a moment:
“Now we beseech you, brethren, by the coming of our Lord Jesus Christ, and by our gathering together unto him, That ye be not soon shaken in mind, or be troubled, neither by spirit, nor by word, nor by letter as from us, as that the day of Christ is at hand.Let no man deceive you by any means: for that day shall not come, except there come a falling away first, and that man of sin be revealed, the son of perdition; Who opposeth and exalteth himself above all that is called God, or that is worshipped; so that he as God sitteth in the temple of God, shewing himself that he is God. Remember ye not, that, when I was yet with you, I told you these things? And now ye know what withholdeth that he might be revealed in his time. For the mystery of iniquity doth already work: only he who now letteth will let, until he be taken out of the way.”
Paul says that the “coming of our Lord Jesus Christ and our gathering together unto Him (the day of Christ)” will not happen until there is a “falling away” first. This falling away is in regards to the church. Paul is saying that an apostasy is coming in the church and many professing Christians will turn from the truth.
Then Paul says that the ‘man of sin’ will be revealed. Notice that Paul called the man of sin the ‘son of perdition’? Who else was called a ‘son of perdition’? John 17:12: “While I was with them in the world, I kept them in thy name: those that thou gavest me I have kept, and none of them is lost, but the son of perdition; that the scripture might be fulfilled.”
Who is Jesus referring to? Judas. Judas was a disciple of Christ in Jesus’ inner circle but was a false brother. Paul is clearly connecting the ‘man of sin’ with Judas. Paul is not saying that Judas will return and exalt himself, but that the ‘man of sin’ will be like Judas in that he will be in the church. Paul also says that this man of sin will exalt himself above God.
This man of sin is a greater manifestation of what was already at work in the church. This “spirit of antichrist” was already at work during John's time. He says in 1 John 2:18-19, "Little children, it is the last time: and as ye have heard that antichrist shall come, even now are there many antichrists; whereby we know that it is the last time. They went out from us, but they were not of us; for if they had been of us, they would no doubt have continued with us: but they went out, that they might be made manifest that they were not all of us."
Who is John referring to? False believers in the church. Here is one example John gives in 3 John 1:9, “I wrote unto the church: but Diotrephes, who loveth to have the preeminence among them, receiveth us not.” Also, Paul, Peter and Jude spend much time discussing False Teachers.
Paul then says about the ‘man of sin’, “Who opposeth and exalteth himself above all that is called God, or that is worshipped; so that he as God sitteth in the temple of God, shewing himself that he is God”
This ‘man of sin’ will be in the “spirit of antichrist” and the “mystery of iniquity”. Paul says “For the mystery of iniquity doth already work: only he who now letteth will let, until he be taken out of the way” The spirit of antichrist was already at work in the church during Paul’s and John’s life. This spirit was in the form of false teachers in the church “And their word will eat as doth a canker: of whom is Hymenaeus and Philetus; Who concerning the truth have erred, saying that the resurrection is past already; and overthrow the faith of some.” (2 Timothy 2:17-18)
Paul says that this spirit of iniquity and antichrist is already in the church but is restrained. What or who is the restraint? Many Christians differ on this. Some think it is the Holy Spirit who will be removed during the rapture, but I do not believe this. The Holy Spirit acts as a restraint against sin, but often is ignored when one slides away from closeness with God. Also, remember Stephen. Stephen was full of the Spirit and all it got him was death. If he had not had the spirit they would have left him alone. So, I do not believe Paul is referring to the Holy Spirit, I believe Paul is referring to the Roman Government.
Edgar Parkyns says in his study of Church History that persecution is God’s instrument to purify His church. For example, when there is no persecution, people who are not sincere will rise into leadership and teach false doctrine. But, when persecution comes, these people are the first to leave. Those who remain in persecution are true followers of Christ and the church is pure. So, I believe that Paul is referring to the Roman government as “him who restrains”. Paul says this restraint will be removed and when it is removed the man of sin will be revealed. Has anything like this happened in history? Yes it has. It is just that we do not want to see it. When the Roman pagan government fell, the persecutions stopped. In fact, the Roman government adopted Christianity as its state religion. You might think this was a good thing but it was not. People were forced to join the church, up until this time a person entered the church through belief, now people are joining for gain. Eventually a "man of sin who exalts himself above God" entered the church in the position of Pope. I know it is unpopular to say that the office of pope is the antichrist/man of sin but what else can a true believer make of it?
Why do I say the antichrist to come is an office and not a particular man? Because 'man of sin' can refer to more than one person just as 'man of God' refers to all Christians. 2 Timothy 3:16-17, "All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness: That the man of God may be perfect, thoroughly furnished unto all good works."
Brothers and sisters, Paul is not telling us to look for a leader of a revived secular roman government, he was telling the church at Thessalonica that they have not missed the coming of the Lord because the man of sin has not appeared. He is also telling us today that we are to look out for false teachers and to remain true to scripture. We are to keep ourselves clean in this world through God and look for our blessed hope and the glorious revealing of Christ in the Second Coming. May He come quickly!