False teachers will be punished. That’s the message Peter conveyed in the second chapter of his second general epistle. Anticipating the presence of false teachers among the saints, he warned about their character and the danger they would present to the faithful.
These false teachers would accumulate followers, but their destruction was guaranteed (2 Peter 2:2-3). To illustrate further the ability of God to punish these individuals, Peter drew upon some historical examples. The text of 2:4-10a is one extended sentence (NKJV). It is a conditional sentence (in the form of "If-then…) with the antecedent (protasis) presented in verses 4-8.
The consequent (apodosis) of the sentence is the Lord knows how to divide (vs. 9). Most parents with more than one child have faced the situation in which there has been some altercation between their children, but neither parent witnessed it. How can we tell who is "guilty" and who is "innocent," especially when each one is pointing at the other? In contrast, God can unerringly separate the godly from the unjust and treat each group accordingly. It may be the tendency of men to think that the unrighteous can "blend" with the godly, making it difficult for God to sort them out, but Peter addressed this misapprehension regarding divine judgment.
The apostle noted three examples of divine judgment. In the first example, Peter remarked that God did not spare the angels who sinned, affirming His ability to reserve certain ones for judgment (vs. 4). Second, the Lord did not spare the world of Noah’s day, "bringing in the flood on the world of the ungodly" (vs. 5). However, in this example, Peter observed that the Lord made a distinction between the righteous and the wicked, saving Noah, a preacher of righteousness, and his immediate family (vs. 5). Although we don’t know the population of the earth at this time, God looked down from heaven and saw, among all of those people, a righteous man and his family.
The third example of judgment concerned the cities of Sodom and Gomorrah. God "made an example out of them" by turning the cities into ashes (vs. 6). At the same time, however, He delivered Lot from the city of Sodom. Even though Lot lived among the wicked, the Lord was fully capable of distinguishing between those who engaged in "filthy conduct" and a righteous man oppressed by such behavior.