Peter is referring back to the examples that he has given. He has shown how the Lord rescued two godly men from trials (Noah and Lot) whilst at the same time ensuring that the unrighteous do not escape judgment (angels or messengers, destruction of the flood, cities of Sodom and Gomorrah). These examples are not just instances to establish a rule, but typological prophecies of eschatological judgment foreshadowing the doom of the wicked.1
9 then the Lord knows how to rescue the godly from trials, and to keep the unrighteous under punishment until the day of judgment,