1 John 5:16 (NIV)
There is a sin that leads to death. I am not saying that you should pray about that.
Christians are often confused when they are commanded to pray for their enemies (Matthew 5:4). We need to understand that Christ isn't commanding us to pray for the well-being and prosperity of our enemies so that they continue to do evil as much as to pray for their salvation and deliverance from sin. Some sin in many ways and can be delivered from their sin through prayer. However, some blasphemed against the Holy Spirit (Mark 3:28-30, Acts 5:3-4), and we should not pray for them as we would be asking God to bless evil. Satan, Judas Iscariot, King Saul, the Pharisees, and others would be examples of blasphemers and apostates who we should not pray for, as we would be asking God to bless evil, which He does not. There are times when, like King David, we can and should pray that God will destroy our enemies (1 Chronicles 14:10-11). Some have not blasphemed against the Lord like Simon Peter, who we should pray for (Luke 22:31-32). Some are apostates like Judas who hang themselves instead of repenting, whom we should not pray for (Matthew 27:5). Such people should be handed over to Satan to be taught not to be blaspheme, not prayed upon (1 Timothy 1:20).