2 Thessalonians 2:6-7

Yet there is something that keeps this from happening now. They knew what it is [or was], because Paul had told them. Johnson thinks [along with many of the Christian fathers] that the "something" was the Roman Empire. Lipscomb [and many others] think it was Paul himself. The attitude which led people to distort the rules of God was already at work, but Paul used his influence and authority to prevent it from growing. When Paul died, this influence of distortion spread rapidly, as history shows. [Some think the chief-angel Michael and his army of angels will prevent the appearance of the Wicked One until Satan is set loose for a little while (see note on 2 Thessalonians 2:3).]