Many picture good and evil, God and Satan, like the Chinese religious symbol of yin and yang, equals, locked in a cosmic battle for control. Nothing could be more untrue. Satan, like all of creation, is under the authority and control of the Creator, subject to Him in every way.
God has an eternal plan for His creation, including Satan, and He’s bringing that plan to His determined end. When things seem out of control, they are still advancing according to God’s eternal will and timing.

I. The Restrainer (2 Thess 2:5-6). The Day of the Lord with it’s falling away and man of sin (2 Thess 2:3) was being kept to a divine and eternal schedule. Something and someone was restraining it. The word restraining (katecho) means to actively and deliberately hold down, hold fast, keep in control. The Thessalonians knew the identity of this restrainer from Paul’s teaching when he was with them.
The restraining power was at work in Paul’s day and greater than sin. It would be removed one day. Because he’d taught this in person, Paul didn’t include the restrainer’s identity. The church only had to remember (2 Thess 2:5) Paul’s teaching while he was with them.
Many suggestions have been offered as to the identity of the restrainer: Israel, the Roman Empire, the Apostle James, Paul, an angel, government, Satan, the antichrist, and the preaching of the gospel. We are convinced by Scripture, that the restrainer is the Holy Spirit.

II. The Mystery of Lawlessness (2 Thess 2:7). The word mystery in the Bible (musterion) describes a once hidden truth now fully revealed (Mk 4:11; Rom 16:25; Col 1:26; 1 Tim 3:9; 3:16). That revealing isn’t by man’s searching but by God’s revelation. There have been mysteries about sin withheld by God until the New Testament, but the power and scope of sin will be fully revealed in the man of lawlessness. He will be the physical embodiment of sin.
This lawless one’s advent is yet future, but lawlessness was already at work supernaturally in Paul’s day (1 Jn 2:18-22). Satan’s power through sin entered the world in the Garden of Eden and mankind in Adam (Rom 5:12-19) and restrained by the Spirit of God. When the restrainer is removed, the lawless one will be revealed, the apostasy begin, and the Day of the Lord start (2 Thess 2:3). The rebellion can’t begin until the revel is revealed.

III. The Brightness of His Coming (2 Thess 2:7). Just before his death, Paul wrote to Timothy that evil men and impostors will grow worse and worse, deceiving and being deceived because sin feeds upon itself (2 Tim 3:13-17). Only the coming of Jesus will put an end to the son of perdition’s reign. Even with sin’s power at work in and through him, God remains supreme and sovereign.
Again, Paul doesn’t create a calendar of events, but writes to comfort the church of God that He’s in control of all things to the very end of all things.
The universe was created from nothing by the simple, yet powerful voice of God through Jesus (Gen 1:1-3; Jn 1:3). Jesus will also be the one to will consume (to put to an end) and destroy (to make useless) the man of sin at the brightness of His coming with the breath of His mouth (Is 11:4; Rev 19:11-21). Jesus’ first appearing was with brightness; His second coming will be no less spectacular.
Jesus will not have to do anything but appear in person to put an end to the man of sin and his reign of wickedness on the earth. He is in control!