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.
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:
Even him, whose coming is after the working of Satan with all power and signs and lying wonders,
And with all deceivableness of unrighteousness in them that perish;
because they received not the love of the truth, that they might be saved.
And for this cause God shall send them strong delusion, that they should believe a lie:
That they all might be damned who believed not the truth, but had pleasure in unrighteousness.
2 Thessalonians 2:1-12
Some people think the restrainer is the church.
Some people think it’s one of God’s Angels, Michael or Gabriel.
Other think it is the Holy Spirit.
That is who I think it is. The Holy Spirit. We will still be here. The Holy Spirit will still be in us.
However, the Holy Spirit will not be free for all to fellowship with.
That’s what I think it means when it says, The night is coming when no man can work.
That is what I think it means when the 5 virgins cannot buy oil. It will be too late. The door will be shut.
That’s what I think it means when it talks about the famine of the Word of God in Amos 8:
Behold, the days come, saith the Lord God, that I will send a famine in the land,
not a famine of bread, nor a thirst for water, but of hearing the words of the Lord:
And they shall wander from sea to sea, and from the north even to the east,
they shall run to and fro to seek the word of the Lord, and shall not find it.
In that day shall the fair virgins and young men faint for thirst. verses 11-13
The Old Testament always had the Holy Spirit present, but it was not freely given to everyone.
So, it will be when He is taken out of the way,
then, the Holy Spirit will only be available to those who are close to God and who follow Him,
who know His word and who speak the truth.
Could there be other theories? Of course.
This is just mine from what I have gathered from studying and considering the restrainer for many years.