The following is a reconstruction of a conversation I had with a fundamentalist Protestant some years ago. I present it for your comment.
Christian: Atheists, by their nature, are immoral. If there is no guarantee of divine justice, there is no reason not to sin and hope to get away with it.
Me: So Christians are without sin because they fear God’s wrath?
Christian: No, Christians are not without sin. All humans are sinful beings by nature. But by accepting the gift of Jesus Christ on the cross, Christians have received forgiveness for their sins and been reborn without the stain of the sin of Adam.
Me: What about sins Christians commit after accepting Jesus. Don’t they have to pay for those?
Christian: No. Jesus’ suffering on the cross is sufficient to wipe away all the sins of the saved.
Me: Then why should a Christian not sin? If someone is saved, they don’t have to fear God’s wrath for their sins, do they?
Christian: No. Their sins have been paid for. But Christians strive to go without sin because the Holy Spirit works within them.
Me: Aren’t you saying that atheists are immoral because they have no fear of divine justice, but Christians are moral even though they have no fear of divine justice?
Christian: No. I’m saying that atheists are immoral because they are fallen and have no reason to be moral, but Christians strive to be moral because they have accepted the Holy Spirit and it works within them.
Me: If it’s not fear of punishment that makes Christians good, then why do you say it’s lack of fear of punishment that makes atheists bad?
Christian: Because all of humanity has a fallen nature, and only through acceptance of Jesus Christ and the Holy Spirit can a mere human hope to battle against temptation to do evil. If you feared punishment, you would accept Jesus Christ as your savior and be reborn.
Me: What about a person who is not a Christian but believes in God’s justice. Might not that person be good in order to avoid punishment, even without accepting Jesus?
Christian: It doesn’t work that way. Because they are done by corrupted humans, good works mean nothing to God. They are like rotting fruit to him because humanity is corrupt. Good works cannot save you from punishment; only the blood of Jesus can wash away your sins.
Me: Then what you’re really saying is that everyone — not just atheists — is immoral because they have not accepted Jesus as their savior. At its heart, divine justice has nothing to do with it.
Christian: I guess in a sense that’s true, but it’s the promise of divine justice that motivates someone to become a Christian. You can’t have one without the other.
Me: Could I sum this up by saying that you think all non-Christians are going to be punished by God and all true Christians are saved, and whether or not any of them sins or does good deeds doesn’t change their fate?
Christian: You’re making it sound horrible on purpose and that’s a gross oversimplification, but in general that’s true.