Passage II Thess 1-3
II Thes 2: (5-8) Do you not remember that when I was still with you I told you these things? And now you know what is restraining, that he may be revealed in his own time. For the mystery of lawlessness is already at work; only He who now restrains will do so until He is taken out of the way. And then the lawless one will be revealed whom the Lord will consume with the breath of His mouth and destroy with the brightness of His coming.
II Thes 2: (5-8) Do you not remember that when I was still with you I told you these things? And now you know what is restraining, that he may be revealed in his own time. For the mystery of lawlessness is already at work; only He who now restrains will do so until He is taken out of the way. And then the lawless one will be revealed whom the Lord will consume with the breath of His mouth and destroy with the brightness of His coming.
The one who now restrains it is removed
I think it is reasonable to assume that it is the Holy Spirit who is restraining the operation of lawlessness in the world at the moment. The interesting point about the removal of the Holy Spirit from the earth is that at the moment the Spirit resides in believers. "Do you not know that your body is the temple of the Holy Spirit who is in you" (1 Corinthians 6: 19). For the Holy Spirit to be removed requires the believers to be removed also. Therefore it is reasonable to assume that the removal of the true church will occur before the final revelation of the "lawless one". This event is referred to as the "Rapture" by many Christians
b. And now you know what is restraining: For now, Satan and the man of sin are being restrained. The principle of their working is now present (the mystery of lawlessness is already at work). But at the right time, the Holy Spirit (He who restrains) who restrains their full revelation will be taken out of the way.
c. Taken out of the way: We should not think that the Holy Spirit would leave the earth during the Great Tribulation. He will be present on the earth during the Great Tribulation because many are saved, sealed, and serve God during this period (Revelation 7:3-14 and 14:1-5), and this can’t happen without the ministry of the Holy Spirit. The Holy Spirit is taken out of the way, not removed.
i. “The phrase is used of any person or thing which is taken out of the way, whether by death or other removal.” (Alford)
ii. Some see this as the end of a dispensation: “The special presence of the Spirit as the indweller of saints will terminate abruptly at the parousia as it began abruptly at Pentecost. Once the body of Christ has been caught away to heaven, the Spirit’s ministry will revert back to what he did for believers during the Old Testament period.” (Thomas)
He who now restrains" . . . The Rapture of the Church
We are told that all who believe Jesus-Yeshua, the promised Messiah, died for their sins, was buried, then raised from the dead, and accept Him as their Lord and Savior (who saves us from Hell) are "born again," and are then indwelt by the Holy Spirit. According to the Bible, you cannot separate the Holy Spirit from the believing Christian. This is God’s promise. So, in order to remove "He who now restrains" (the Holy Spirit), God must also remove the body of believers who are alive at that time. This is why many believe the man some call the 'Antichrist' cannot be revealed until after the Rapture of the Church (admittedly a pretty 'hard to comprehend' prophecy) . . . so we don't spend too much time trying to figure out who this guy is. Also, since there doesn't appear to be any obvious prophecies concerning America specifically during the Tribulation period, some feel the U.S. may be "neutralized" as an international restraining force at or around this same time . . .
Conclusion: And then the lawless one will be revealed, whom the Lord Jesus will overthrow with the breath of his mouth and destroy by the splendor of his coming. The coming of the lawless one will be in accordance with the work of Satan displayed in all kinds of counterfeit miracles, signs and wonders, and in every sort of evil that deceives those who are perishing. They perish because they refused to love the truth and so be saved. For this reason God sends them a powerful delusion so that they will believe the lie and so that all will be condemned who have not believed the truth but have delighted in wickedness.