As we can see in 2 Thessalonians, Daniel and Revelation - Michael is the one who now holds back Satan. Satan is the one behind lawlessness and sin (1 John 3:4-8). When Michael throws Satan to earth, Satan will be unrestrained during the Great Tribulation and he will give his power to the Antichrist to pursue Israel and the followers of Christ.
The dragon [Satan] gave the beast [Antichrist] his power and his throne and great authority (Revelation 13:2)
He [Antichrist] will become very strong, but not by his own power [Satan’s]. He will cause astounding devastation and will succeed in whatever he does. He will destroy the mighty men and the holy people (Daniel 8:24).
