Q - Who is the restrainer that is taken out of the way before the antichrist is revealed?

A - It's not the complete church it is the "overcomers" the bride of Christ.

The Holy Spirit is not taken from the earth. He is taken "out of the way,"

What is the differences in Christians who allow the Holy Spirit to rule their lives and those who do not?

Well there's a big differences, the Holy Spirit is working through those of us who have the characteristics of a Philadelphia Christian. When we are removed in the first fruits rapture (the separation) then the restraining force is removed because it is within us and the antichrist is free to deceive the lukewarm Laodiceans and the backslidden Christians that will be left behind.

The Philadelphia Christian is the one who will be taken in the Firstfruits Rapture (taken out of the way). I have had many questions from other Christians asking me to identify the characteristics of a Philadelphia Christian. The primary answer is that the Philadelphia Christian bears the Fruit of the Spirit, which is love, joy, peace, patience, kindness, goodness, faithfulness, gentleness, and self-control. The Philadelphia Christian bears this fruit because he is filled or controlled by the Holy Spirit. He is filled or controlled by the Holy Spirit because he reads his Bible and allows the Word of God to be firmly implanted in his being. Only Christians with these characteristics are filled with the Holy Spirit and they alone will be taken in the rapture.

2 Thessalonians 2:3-12.
3 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;

In verse 3 the words "falling away" is a mistranslation, it is from the Greek word "apostasia" and is defined as "departure" the original word there should have been translated to "catching away" or "departure" this is referring to the "separation" of first fruits rapture.

4 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.

Verse 4 is referring to the antichrist.

5 Remember ye not, that, when I was yet with you, I told you these things? 6 And now ye know what withholdeth that he might be revealed in his time. 7 For the mystery of iniquity doth already work: only he who now letteth will let, until he be taken out of the way.

Verse 7 is saying that the true Christians "overcomers" allow the evil one to work somewhat but he cannot come into full power as long as they are around so they will be removed before the antichrist can take control of the world. At this point the first fruits rapture (separation) will take place removing the "overcomers" from the earth leaving behind the lukewarm and backslidden Christians that do not allow the Holy Spirit to work through them.

8 And then shall that Wicked be revealed, whom the Lord shall consume with the spirit of his mouth, and shall destroy with the brightness of his coming: 9 Even him, whose coming is after the working of Satan with all power and signs and lying wonders, 10 And with all deceivableness of unrighteousness in them that perish; because they received not the love of the truth, that they might be saved. 11 And for this cause God shall send them strong delusion, that they should believe a lie: 12 That they all might be damned who believed not the truth, but had pleasure in unrighteousness.

The Holy Spirit will not be removed, people will still get saved this could not happen if the Holy Spirit were to be removed.

We know people will get saved because that is the purpose of the "Two Witnesses" and the "144,000" Jewish evangelists who will be preaching the gospel of Christ to the whole world during the first half of the Tribulation.

So the restrainer that will be removed before the antichrist is revealed are the "overcomers" that is to say the Christians that have the characteristics of a Philadelphia Christian that will be removed with the first fruits rapture. So in a way it is the Holy Spirit but just the part of the Holy Spirit that lives within the overcomers and he is not removed he is just taken out of the way.