21:8 But the cowardly, the unbelieving, the vile, the murderers, the sexually immoral, those who practice magic arts, the idolaters and all liars—they will be consigned to the fiery lake of burning sulfur. This is the second death.”
BUT
This preposition indicates that the list which follows does not include any of the VICTORS in the previous verse. Furthermore, this list is associated with seven demonic realms as detailed in Revelation 13:1.
the COWARDLY,
The Amplified Bible expands this with 'ignoble, contemptible, cravenly lacking in courage, and cowardly submissive'. We can see how this is tied to unbelievers (next item in the list), but most likely applies to nominal Christians also (Mark 8:31-38).
the UNBELIEVING,
The Amplified Bible adds 'faithless' to UNBELIEVING. This is the only class of people for which there is no forgiveness (1 John 5:6-12, 1 Corinthians 6:9-11, and John 3:16-18-21).
the VILE,
'Depraved and defiled with abominations' is how the Amplified Bible expands this class. The abominable are described in Titus 1:15-16. Furthermore, there was nothing good about the great harlot whose cup held abominations (Revelation 17:4).
the MURDERERS,
Since this is the final list of those who will experience the second death, the broad definition of murder as John writes in an earlier letter (1 John 3:11-15-24) should be used.
the SEXUALLY IMMORAL,
The Amplified Bible calls this group 'lewd and adulterous'. This group is the only one where their sin is sexual in nature. Given how much is written about sexual sins in the Bible, it is rather surprising that this is only a small part of the condemned.
those who PRACTICE MAGIC ARTS,
'Practicers of magic arts' is how the Amplified Bible identifies these people. Here's what God thinks about this group (Deuteronomy 18:9-13).
the IDOLATERS and
With a broad brush, the Amplified Bible says this group are 'those who give supreme devotion to anyone or anything other than God'. The test for an idolater is found in 1 Timothy 4:1-10. If you don't have the word of God in you or don't practice an extensive time in non repetitious prayer, you are susceptible to IDOLATRY and LYING (next item in the list).
Lest we think this is an external devotion to anyone or anything other than God, Paul in Colossians 3:1-5-8-17 makes IDOLATRY PERSONNAL. The reader is able to figure out who is the idol.
and all LIARS --
'Those who knowingly convey untruth by word or deed' is how the Amplified Bible tags this group. The father of all liars is the devil (John 8:31-44-47), and the devil already is in the lake of fire (Revelation 20:10).
they will be consigned to the fiery lake of burning sulfur. This is the "SECOND DEATH".
This is probably the saddest list in the Bible for this SECOND DEATH is a permanent and FOREVER DEATH. You may have heard the expression, "He died a slow death"; well this is forever longer slow DEATH. Imagine all the evil that you can and then think how you would live within that evil (and much worse) forever. The alternative, asking for forgiveness for your sins and accepting Jesus Christ as your Master, would seem to me to be a better choice.