"Having a form of godliness, but denying the power thereof: from such turn away." (2 Timothy 3:5)
Those with a "form of godliness" are much more difficult to recognize than those who are openly wicked. Jesus gave His most harsh criticism to the hypocritical leaders of the religious sects of His day. Jesus also warned of "false prophets, which come to you in sheep's clothing, but inwardly they are ravening wolves" (Matthew 7:15).
On another occasion, Jesus illustrated the challenge of identifying those who looked like God's people but were really "tares" that the Enemy had sown among the wheat. In His parable, Jesus indicated that even the "servants of the householder" might uproot the wheat along with the tares (Matthew 13:24-30). The Corinthian church was warned about the same problem when they were told that "Satan himself is transformed into an angel of light" (2 Corinthians 11:14).
We are strongly urged to "turn away" from these kinds of people. They have the ability to cause serious damage among the churches. They will "creep" into "houses" (a metaphor for churches—1 Timothy 3:15) and will lead "silly women" away with many different desires (2 Timothy 3:6). They will resist the truth and will have power like the magicians of Egypt who deceived Pharaoh and opposed Moses. And like those magicians, their minds are corrupt (focused on sin) and are already condemned (2 Timothy 3:8).
The good news is that they will be forcibly stopped and exposed as foolish (2 Timothy 3:9). Peter notes that they will have swift destruction (2 Peter 2:1-3) and will utterly perish in corruption (2 Peter 2:12-13). Like the magicians who produced snakes, blood for water, and frogs aplenty (Exodus 7-8), they will be unable to go any further and will be forced to say, "This is the finger of God" (Exodus 8:19). HMM III