Although the term is not found in the Hebrew Bible, Sysling, in his study (1996) of Teḥiyyat ha-metim (“resurrection of the dead”) in the Palestinian Targums, identifies a consistent usage of the term “second death” in texts of the Second Temple period and early rabbinical writings. In most cases, the “second death” is identical with the judgment, following resurrection, in Gehinnom at the Last Day.
In Targum Neofiti (Neof.) and the fragments (FTP and FTV), the “second death” is the death that the wicked die.
Targum Isaiah has three occurrences. The first is 22:14 where the Aramaic paraphrases the Hebrew as “This sin will not be forgiven you until you die the second death.”  The final two examples are from Targum Isaiah 65 which sets the scene for an apocalyptic final battle. Targum Isaiah 65:6 paraphrases the Hebrew in line with the interpretation of the penultimate verse of the Hebrew Isaiah, found in the Gospel of Mark, where “their worms does not die” is equated with Gehinnom. Here both Targum Isaiah and Gospel of Mark supply the term “Gehinnom”, where Hebrew Isaiah simply concludes with the heaps of corpses following the last battle where “their worms do not die”, making no further eschatological extension into resurrection and judgment.
Targum Jeremiah 51:17 has the Aramaic “they shall die the second death and not live in the world to come”, which appears to depart from the other Targum uses in not being explicit that the second death is after resurrection but may instead be an exclusion from resurrection.
The majority reading of Targum Psalm 49:11 has the Aramaic translation “For the wise see that the evildoers are judged in Gehinnom”. However, several manuscripts, including Paris No.10, Montefiore No.7, and Targum of Salomos 113 have the variant Aramaic translation “He sees men wise in wickedness, who die a second death, and are judged in Gehinnom”.
David Kimhi (Toulouse, c.1160-Narbonne, 1235) considered the phrase to mean “the death of the soul in the world”.
The term “second death” occurs four times in the New Testament, specifically in Revelation 2:11, 20:6, 20:14 and 21:8. According to Revelation 2:11 and 20:6, those who overcome the devil’s tribulation, are holy and have part in the first resurrection will not experience the second death. Revelation 20:14 and 21:8 then identify the second death with the lake of fire. In Revelation 21:8 we read: “[A]s for the cowardly, the faithless, the polluted, the murderers, the fornicators, the sorcerers, the idolaters, and all liars, their place will be in the lake that burns with fire and sulfur, which is the second death.”
When people are saved, they are not subject to the second death. They die only the first, earthly death. However, an unsaved person will experience two deaths: the first death and then after the resurrection the second death which is usually interpreted as a kind of torment for all eternity. This traditional view was elucidated by Lactantius:
We term that punishment the second death, which is itself also perpetual, as also is immortality. We thus define the first death: Death is the dissolution of the nature of living beings; or thus: Death is the separation of body and soul. But we thus define the second death: Death is the suffering of eternal pain; or thus: Death is the condemnation of souls for their deserts to eternal punishments.
Christian universalists reject the notion of endless torment and therefore offer different interpretations. For instance, Gregory of Nyssa understood the second death as a cleansing, albeit painful process. He wrote that “those still living in the flesh must as much as ever they can separate and free themselves in a way from its attachments by virtuous conduct, in order that after death they may not need a second death to cleanse them from the remnants that are owing to this cement of the flesh”. Annihilationists, including some Anglicans, some Lutherans, all Seventh-day Adventists and Jehovah’s Witnesses, and others, also oppose the idea of eternal suffering but believe that the second death is an actual second death and that the souls condemned to it at the final judgment will be annihilated.
- Harry Sysling Teḥiyyat ha-metim: the resurrection of the dead in the Palestinian Targums p222 1996 -“Here the second death is identical with the judgment in Gehinnom. The wicked will perish and their riches will be given to… The second death in the Apocalypse In the Apocalypse of John, the second death is mentioned several times….
- Sysling, p220
- Martin McNamara, Targum and Testament revisited: Aramaic paraphrases of the Hebrew p.226 2010 – 359
- Sysling Teḥiyyat ha-metim: the resurrection of the dead in the Palestinian Targums p221 1996
- Israel Abrahams Studies in Pharisaism and the Gospels Page 44 “Qimhi’s interpretation that the Second Death refers to the “death of the soul in the world to come” cannot be accepted without qualification. For in its paraphrase of Isaiah lxv. 6 the Targum uses the expression: “I will deliver.”
- “Divine Institutes, Book II”. Newadvent.org. Retrieved 6 July 2019.
- “On the Soul and the Resurrection (St. Gregory of Nyssa)”. Newadvent.org. Retrieved 6 July 2019.