Because the coming other-christ is called the Man of Lawlessness by Paul in Thessalonians, we tend to think of sins as being the hallmark of his followers and his work. It may shock you to find out what that sin consists of.
When the revivalist miracle-workers of the last days cite their works as a qualification of entrance into heaven, the Lord rejects them with these words:
Matt 7: 21-24 “Not everyone who says to Me, ‘Lord, Lord,’ shall enter the kingdom of heaven, but he who does the will of My Father in heaven. Many will say to Me in that day, ‘Lord, Lord, have we not prophesied in Your name, cast out demons in Your name, and done many wonders in Your name?’ And then I will declare to them, ‘I never knew you; depart from Me, you who practice lawlessness!’