For the mystery of lawlessness already works. Only there is one who restrains now, until he is taken out of the way.
The "mystery of iniquity" is the work of the antichrist that labors against God and His ways. The mystery refers to undeveloped sins that are already at work; and once they were fully developed they would attempt to destroy the simplicity of the gospel. It has direct aim at the doctrine of the church; therefore, Jesus says, "And many false prophets shall rise, and shall deceive many. And because iniquity shall abound, the love of many shall wax cold" (Matthew 24:11-12). In verse 9 of 2 Thessalonians, Paul will relate some of the different types of works that were being used to trick and confuse the Lord’s people—"signs" and "lying wonders." The Apostle John says, "And every spirit that confesseth not that Jesus Christ is come in the flesh is not of God: and this is that spirit of antichrist, whereof ye have heard that it should come; and even now already is it in the world" (1 John 4:3).