2 Peter 2:20-21, . . . For if after they have escaped the pollutions of the world through the knowledge of the Lord and Saviour Jesus Christ, they are again entangled therein, and overcome, the latter end is worse with them than the beginning. 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. . . .
Romans 4:4-5. Not the mere knowing by which one is saved, but trusting God. Genesis 15:6.
2 Peter 2:20. For if, after they have escaped the defilements of the world through the knowledge of our Lord and Savior Jesus Christ, they are again entangled in them and overpowered, the last state has become worse for them than the first.
21. For it would have been better for them never to have known the way of righteousness than, after knowing it, to turn back from the holy commandment that was passed on to them.
22. It has happened to them according to the true proverb,
“The dog turns back to its own vomit,”
and,
“The sow is washed only to wallow in the mud.”
This passage of scripture is not about “mere knowing,” it is about persons who had fully known (ἐπιγνοῦσιν BDAG, P. 369) the “way of righteousness.” That is, it is about persons who
had personally experienced and enjoyed having escaped, through their personal relationship with Christ, the defilements of the world.
Acts 9:2. and asked him for letters to the synagogues at Damascus, so that if he found any who belonged to the Way, men or women, he might bring them bound to Jerusalem.
Acts 19:25. He had been instructed in the Way of the Lord; and he spoke with burning enthusiasm and taught accurately the things concerning Jesus, though he knew only the baptism of John.
26. He began to speak boldly in the synagogue; but when Priscilla and Aquila heard him, they took him aside and explained the Way of God to him more accurately.
Acts 19:9. When some stubbornly refused to believe and spoke evil of the Way before the congregation, he left them, taking the disciples with him, and argued daily in the lecture hall of Tyrannus. {Other ancient authorities read [of a certain Tyrannus, from eleven o'clock in the morning to four in the afternoon]}
Acts 19:23. About that time no little disturbance broke out concerning the Way.
Acts 22:4. I persecuted this Way up to the point of death by binding both men and women and putting them in prison,
Acts 24:14. But this I admit to you, that according to the Way, which they call a sect, I worship the God of our ancestors, believing everything laid down according to the law or written in the prophets.
Acts 24:22. But Felix, who was rather well informed about the Way, adjourned the hearing with the comment, "When Lysias the tribune comes down, I will decide your case.”
Notice that in these Scriptures from Acts, the word “Way” is capitalized in the NRSV and in some other translations as well (see, for examples, the NAB, the RSV, and the ESV). It is capitalized because it is what the earliest Christians called their belief system, and what we today call Christianity. For
very extensive documentation, please see Craig S. Keener’s 4,615-page commentary on Acts published by Baker Academic as
Acts: An Exegetical Commentary in four very large volumes during the years 2012-2015.
This designation for the Christian faith is sometimes expanded in the Scriptures to “the way of truth,” (2 Peter 2:2) and “the way of righteousness” (2 Peter 2:21” where the meaning is essentially the same but emphasizes the experience of being in Christ. That this is the correct interpretation is confirmed in the very next verse where a sow that has been thoroughly washed (λουτροῦ ) rather than just rinsed off returns to the mud—an allusion to Titus 3:5,
5. he saved us, not because of deeds done by us in righteousness, but in virtue of his own mercy, by the washing of regeneration and renewal in the Holy Spirit, (RSV)
In this verse, Paul uses the cognate noun of the aorist participle used in 2 Peter 2:22.
(All quotations from Scripture are from the NRSV unless otherwise noted)