2 Peter 2:21 21For it would have been better for them not to have known the way of righteousness than after knowing it to turn back from the holy commandment delivered to them.
This verse hints at the kind of judgment a false teacher should expect from God. The Bible implies that there will be levels of judgment and that each person will receive what he or she deserves (Romans 2:6-8). God will avenge those who do evil. Those in positions of leading God’s people will be held to a higher standard because they are “stewards of divine mysteries” (1 Corinthians 4:1). Peter is specifically speaking about those who had believed, experienced salvation, and then turned away from the truth. Peter could recall people like Judas, whom he had known for at least three years. He might also be remembering the words of Jesus in Matthew 26:24, “The Son of Man will go just as it is written about him. But woe to that man who betrays the Son of Man! It would be better for him if he had not been born.”
The key idea is to know the way of righteousness, which likely refers to the word of truth found in the gospel. The first step of apostasy is to begin to question or ignore this truth. The holy commandment is undefined, but the context would suggest it refers to God’s revelation through the authentic and true prophets of the Old Testament who spoke of the coming of the Messiah (1:19-21). Peter’s words seem harsh in this verse, and he likely intended them to be strong and shocking, which should alert the readers to the seriousness of their situation. To know and experience the truth of Jesus and to turn from it in selfishness to pursue the deceit of the world is a serious matter. We must be ever vigilant in our desire to know God. The truth really does matter.