Introduction
Begin your sermon with a reflection on the reality of life in this world and how it often seems to go well with those who have no concern for God. Comment on how this reality can prompt us to doubt God’s justice as well as question whether or not there really will be a day of judgment in the future.
Also consider how the presence of false teachers adds to confusion. They claim to follow Christ, yet they live as pagans, giving the idea that one can belong to God without any need for repentance. This discourages believers from pursuing godliness, as if godliness is not worth the effort.
Certainty of judgment despite what we see
Explain how Peter seeks to support his claim that judgment is coming, and that he needs to provide support because the false teachers look at the world and do not see any immediate judgment for sinful behaviour.
Explain how the angels, the flood, and Sodom and Gomorrah are confirmations that God acts to judge sin. If he has done so in the past, he will do so in the future.
Apply: if judgment is certain, we must not believe the lie which says that we can indulge our sinful nature without any consequence.
Safety in Christ
Explain how and why Noah and Lot escaped judgment.
Explain the doctrine of justification through faith in Christ. Confirm that this doctrine was also found in the stories recounted by Peter.
Apply: if we belong to Christ, we do not have to fear judgment. Our judgment has already taken place when Christ died for our sins (see 2 Corinthians 5:20–21).
Apply: if we belong to Christ, we do not despair when we look around us and see the ungodly prosper. We trust that God will set things right when he returns in glory.
Apply: if we belong to Christ, we reject the claims of the false teachers that the Christian life does not involve repentance. Instead of indulging our sinful desires we seek to change and live in obedience to Christ.
Conclusion
God is just and he will act to bring judgment on those who do wrong. Even if we do not see God’s justice exercised in our day, we can trust that it will be seen clearly when Christ returns in glory. The fact that Christ will return to bring judgment and punish those who do wrong should not fill us with fear if we belong to Christ. If we belong to him, our judgment has already come and through faith his righteousness has been granted to us. The day of judgment will therefore be a day of salvation. This truth does not free us to indulge our sinful natures, but inspires us to pursue godliness in the here and now. Let us therefore not give heed to the teachings of those who deny judgment or claim that we can live as we please without any need for repentance. Let us serve Christ now, trusting that we are made right with God because of what he has done. His grace has saved us, his grace protects us, and one day his grace will deliver us to glory.
4 For if God did not spare angels when they sinned, but cast them into hell and committed them to chains of gloomy darkness to be kept until the judgment;