2 Peter 2:20 For if they have escaped the pollutions of the world through the knowledge of the Lord and Saviour Jesus Christ (they were saved by trusting Christ and the Cross), they are again entangled therein, and overcome (proclaims the fact that if the Believer ceases to place his Faith and trust in what Jesus did at the Cross, that entanglement in the pollutions of the world will once again become a fact; it cannot be otherwise), the latter end is worse with them than the beginning.
2 Peter 2:21 For it had been better for them not to have known the way of Righteousness, than, after they have known it, to turn from the Holy Commandment delivered unto them.
2 Peter 2:22 But it is happened unto them according to the true Proverb [Proverb 26:11], The dog is turned to his own vomit again; and the sow that was washed to her wallowing in the mire. (this completely refutes the Unscriptural Doctrine of Unconditional Security, and gives the reason...a departure from Christ and the Cross.)
Jesus Speaks...
Luke 11:23 He who is not with Me is against Me (presents the fact that there is no neutrality with Christ): and he who gathers not with Me scatters (everything is either of the Devil or of Christ, there is no middle ground)
Luke 11:24 When the unclean spirit is gone out of a man (concerns the efforts of man, whatever they may be, to save himself other than by Christ and Him Crucified), he walks through dry places (waterless, out of the body), seeking rest (concerns the "unclean spirit" which has gone out); and finding none, he says, I will return unto my house whence I came out (unless Christ affects the work, whatever it might be, it is not truly affected)
Luke 11:25 And when he (the evil spirit) comes, he finds it swept and garnished (means it was filled with that other than Christ)
Luke 11:26 Then goes he, (the evil spirit), and takes to him seven other spirits more wicked than himself (concerns the reoccupation by demon spirits) and they enter in, and dwell there (proving that most of the world is controlled by demon spirits): and the last state of that man is worse that the first (this was the state of Israel after they had rejected Christ, which ultimately led to their total destruction)