The Restrainer in 2 Thessalonians 2:7

We learn from the prophet Daniel that Michael's work is to "stand firmly against" or "restrain" the forces of evil.

Daniel 10:2121 “However, I will tell you what is inscribed in the writing of truth. Yet there is no one who stands firmly with me against these forces except Michael your prince.

Also, in Daniel 12:1 it says Michael will arise right before the start of the Great Tribulation

Daniel 12:1“At that time shall arise Michael, the great prince who has charge of your people. And there shall be a time of trouble, such as never has been since there was a nation till that time.

Take a look at 2 Thessalonians 2:7-8 concerning the restrainer:

2 Thessalonians 2:7-8
7 For the mystery of lawlessness is already at work. Only he who now restrains it will do so until he is out of the way. 8 Then that lawless one will be revealed whom the Lord will slay with the breath of His mouth and bring to an end by the appearance of His coming;

Once the restrainer is taken out of the way, the Antichrist will be revealed (halfway through the 70th week).  When the Antichrist begins to exercise his wrath, the apostate believers will flee from the church and the falling away will begin.

2 Thessalonians 2:3, 9-12
3 Let no one in any way deceive you, for it will not come unless the apostasy comes first, and the man of lawlessness is revealed, the son of destruction... 9 that is, the one whose coming is in accord with the activity of Satan, with all power and signs and false wonders, 10 and with all the deception of wickedness for those who perish, because they did not receive the love of the truth so as to be saved. 11 For this reason God will send upon them a deluding influence so that they will believe what is false, 12 in order that they all may be judged who did not believe the truth, but took pleasure in wickedness.

After the appointed time for the Antichrist has past to exercise his wrath on God's people, the Lord will halt his work at His coming and eventually bring him to an end.

Matthew 24:15
15 “Therefore when you see the ABOMINATION OF DESOLATION which was spoken of through Daniel the prophet, standing in the holy place (let the reader understand),

Matthew 24:21
21 For then there will be a great tribulation, such as has not occurred since the beginning of the world until now, nor ever will.

Revelation 12:7-9
7 And there was war in heaven, Michael and his angels waging war with the dragon. The dragon and his angels waged war, 8 and they were not strong enough, and there was no longer a place found for them in heaven. 9 And the great dragon was thrown down, the serpent of old who is called the devil and Satan, who deceives the whole world; he was thrown down to the earth, and his angels were thrown down with him.

The following four passages describe the events related to the same end time period of distress and persecution.

	Event	Afterwards
1	Antichrist is revealed Matthew 24:15	Will be a time of unequaled distress. Matthew 24:21
2	Michael, Israel’s protector arises. Daniel 12:1	Will be a time of distress as never before. Daniel 12:1
3	Michael defeats Satan and hurls him to the earth. Revelation 12:7-9	Satan is on the earth and furious.  He empowers the Antichrist to pursue Israel and the church Revelation 12:12-17; 13:1-2
4	The restrainer is taken out of the way and the Antichrist is revealed. 2 Thessalonians 2:7-8	Will be a time of great evil and strong deception causing many to perish. 2 Thessalonians 2:3, 9-12

The logical conclusion is that Michael is the restrainer of 2 Thessalonians 2:7. At the appointed time, Michael is going to arise from protecting Israel (2) and will war with Satan in heaven and cast him to the earth (3).