Warning against False Teachers: 2 Peter 2: 1-9. 
In this chapter Peter warns the believers against false teachers.  He draws a contrast between God's Word and the deception of false teaching.  Paul warned that false teachers will come from within the Church (Acts 20:29, 30).  These are professing Christians secretly bringing destructive heresies along with true doctrines in the church. Peter urges believers to pay close attention to the teachings of the apostles. The common denominator of their heresy is their denial of the deity of Jesus Christ.  Also they deny the reliability of the Bible, trinity, the virgin birth of Christ, His bodily resurrection, eternal judgment and the reality of miracles in the Bible. False teachers claim they have special revelation and knowledge of God. They promise freedom but they themselves are slaves to sin. They are reformed people but never  born again. False teachers were unclean before they were reformed and remain unclean after they say they have been changed (2 Peter 2:20-22). This passage does not teach that believers can lose their salvation.  Reformation is dangerous because it can give false impressions about salvation. God is just, and he will ensure that those who exploit others with lies will be judged.  He will punish the wicked but rescue the godly (2:9).  God rescued Lot, a righteous man who was distressed by the  sinful conduct of the lawlessness (2:7).  He became the beneficiary of Abraham’s prayer and God’s mercy. As Christians we should become a channel for God’s grace to work in the lives of unbelievers. We are the salt of the earth and the light of the world, so that others will see Christ in and through us.  False teachers will bring upon themselves swift destruction.  So Peter warns believers not to fall into their destructive deceptiveness.

Marks of false teachers: 2 Peter 2:10-22 
This is a difficult passage because it appears to give the impression that those who have been saved can fall away.  But a careful reader will note that, as in Hebrews 6:4-9, these people have never actually been saved or freed from their enslavement to sin (2:19). They have given the appearance of being part of the church but never experienced the transforming  power of godliness. Their knowledge of Christ was superficial (2 Peter 2:20).  Only those who receive the gospel with a humble heart will be saved.  They experience transforming work of the Holy Spirit that can never be reversed. Those who fall away show that they were never truly saved (1 John 2:19). Their hearts are more hardened to the appeal of the gospel because they think they have already been saved (2 Peter 2:20-21).  They live according to their natural instinct.

They deny the deity of Christ. 2 Peter 2:1

They blaspheme the truth. 2 Peter 2:2

They twist the truth and exploit new believers for personal gain. 2 Peter 2: 3, 15.

They are self-willed people. Slander even angels. 2 Peter 2:10, 11.

They are immoral and act according to their natural instincts. 2 Peter 2: 12.

They make fun of things they do not know. They are not much help to anyone.  2 Peter 2: 12.

They promise freedom yet they themselves are slaves to sin. 2 Peter 2: 19.

They deny the second coming of Christ. 2 Peter 3: 4, 5.

They will utterly perish in their own corruption. 2 Peter 2:10-14.

They can not escape the judgment of righteous God. 2 Peter 2: 4-9.

But the righteous will be preserved by God in His mercy. 2 Peter 2: 7.