New King James Version (NKJV)
2 Peter 2
19 While they promise them liberty, they themselves are slaves of corruption; for by whom a person is overcome, by him also he is brought into bondage.
20 For if, after they have escaped the pollutions of the world through the knowledge of the Lord and Savior Jesus Christ, they are again entangled in them and overcome, the latter end is worse for them than the beginning.
21 For it would have been better for them not to have known the way of righteousness, than having known it, to turn from the holy commandment delivered to them.
22 But it has happened to them according to the true proverb: "A dog returns to his own vomit," and, "a sow, having washed, to her wallowing in the mire."
2 Peter 3
1 Beloved, I now write to you this second epistle (in both of which I stir up your pure minds by way of reminder),
2 that you may be mindful of the words which were spoken before by the holy prophets, and of the commandment of us, the apostles of the Lord and Savior,
3 knowing this first: that scoffers will come in the last days, walking according to their own lusts,
4 and saying, "Where is the promise of His coming? For since the fathers fell asleep, all things continue as they were from the beginning of creation."
5 For this they willfully forget: that by the word of God the heavens were of old, and the earth standing out of water and in the water,
6 by which the world that then existed perished, being flooded with water.
7 But the heavens and the earth which are now preserved by the same word, are reserved for fire until the day of judgment and perdition of ungodly men.