Schaff, Philip. History of the Christian Church (The Complete Eight Volumes in One). Amazon Kindle Edition, 2014.
Volume 2, Ante-Nicene Christianity A.D. 100-325, “Chapter 12. The Development of Catholic Theology in Conflict with Heresy” Sections 137-158, Loc. 18758-20235.
§ 157. After Judgment. Future Punishment.
After a brief bibliography, Schaff observes that Christians have always agreed that the righteous “shall inherit eternal life and enjoy the blessed communion of God forever and ever” (Schaff 2014, Loc. 20097). However there have been three different ideas about the “impenitent.”
First, the orthodox idea is that of everlasting punishment. This is consistent with most Jewish teaching. Schaff also finds it in Ignatius, Hermas, and Justin Martyr (Schaff 2014, Loc. 20104). Schaff describes the views of Justin in some detail, as well as those of Irenaeus, Hippolytus, Tertullian, and Cyprian (Schaff 2014, Loc. 20120).
A secondary view is that of a “final annihilation of the wicked” (Schaff 2014, Loc. 20127). In this view the sinful soul is completely destroyed. Schaff observes that the view has been attributed to Justin Martyr and Irenaeus, but he asserts that they spoke too strongly of eternal punishment to think otherwise.
A third view is that of a final restoration of all to holiness. Schaff notes that this view says repentance, conversion and salvation are, in the end, useless (Schaff 2014, Loc. 20135). Origen did fall into this view, but with some moderation. Gregory of Nyssa was more adamant in his universalism. (Schaff 2014, Loc. 20143).