The first five chapters of this work are a Jewish expansion of 2 Kings, detailing the martyrdom of Isaiah. Chapters 6-11 are a Christian work which detail Isaiah’s ascension through the seven heavens. This section is akin to the apocalyptic literature of Enoch in that Isaiah’s soul is ushered through various stages of heaven. Each section is a composite of various sources. This complicates the dating of the book. The Jewish section was likely written in Hebrew and translated into Greek. Hebrews 11 appears to refer to the martyrdom of Isaiah (“some were sawn asunder”) or the same tradition that Isaiah the prophet was martyred by being sawn in half. This would imply a date prior to the late first century.
The activities of demons are very important in the Martyrdom of Isaiah. It is the demon Sammael Milkira who causes Manasseh to go astray and Beliar possesses him and prompts him to kill the prophet. Near the end of Hezekiah’s life he calls Manasseh, his only son, in order to give him a final charge (ch. 1). Isaiah the Prophet is also present as well as the prophet’s son, Josab (Shear-Jashub in Is. 7:3). He tells the boy the “words of righteousness” which he has seen, including eternal judgments, Gehenna, and the activities of demons (princes of this world.) There is an implication that Hezekiah has had visionary experiences himself which were recorded by his secretary. Isaiah tells the king this speech will have no effect on Manasseh and that he will rebel against the word of the Lord.
The demon Sammael Milkira will indwell Manasseh. Beliar will also indwell Manasseh and he will lead many to desert the faith. Isaiah even predicts his own martyrdom. This creature was originally an archangel, but he enticed the serpent to tempt Eve. He is a Satan in Debarim rabba 11 and the angel of death, Targum Jeremiah (OTP 2:157 note u). Sammael Milkira is mentioned in the Greek Apocalypse of Baruch 4:8 (he planted a vine in the garden to tempt Adam) and 9:7 (when he “took the serpent as a garment.”
All that Isaiah predicted happens (ch. 2). Manasseh does not obey his father and he served Satan instead. Witchcraft, magic, divination, auguries, fornication, adultery, and the persecution of the righteous all increase, so Isaiah and the rest of the prophets withdraw from Jerusalem to Bethlehem, then to a mountain in a desert place. There they eat noting but bitter herbs for two years. There is a short story inserted at this point which seems to have little to do with the rest of the book other than to introduce the a false prophet named Belkira. This man accused the prophet Micaiah who is eventually martyred himself. Compare OTP 2:158 note o and 159 note b; it is possible the name in chapter two is not the same as the name in chapter 3.
In chapter 3, Belkira the false prophet discovers Isaiah’s hiding place and accuse these prophets of prophesying against Israel and Judah (which is most likely true at this point!) The king is convinced and Isaiah is arrested. Verses 13-31 are a Christian interpolation describing the death and resurrection of Christ, the descent of the Holy Spirit and the spread of the gospel. Eventually the church will abandon the teaching of the twelve apostles and there will be many wicked elders and shepherds who do wrong for their sheep.
Chapter 4 seems as though it is from yet another source, likely Christian. The content seems to be based on either the Olivet Discourse or the book of Revelation. It is more likely this chapter reflects the sort of Christian reflection on Daniel and Antiochus IV Epiphanies represented by these two Christian texts. Isaiah is speaking in the first person to Hezekiah and Josab about the return of Christ and associated apocalyptic judgments. After the twelve apostles plant the gospel throughout the world, Beliar will come in the form of a king. This king is a “murderer of his mother,” a stock description of Nero in other apocalyptic literature. People will sacrifice to this king and worship him. He will do miracles in every district and set up his image everywhere (the “abomination which causes desolation,” possibly emperor worship).
The duration of his reign will be three years, seven months and twenty-seven days (or 1, 335 days total, cf. Dan. 12:12). After this time “The Beloved” will speak from heaven and “reprove in anger the world.” All which is written in the prophets will be fulfilled, a list of the prophets is included in 21-22. The Minor Prophets appear in the order of the LXX and the “word of the righteous Joseph” are included. This may be a reference to the Prayer of Joseph (OTP 2:699-714). This chapter is important because it shows an eschatological program outside of the biblical material used by at least some in the early church which included the elements of the Olivet Discourse and Revelation.
Because of the vision Beliar is enraged with Isaiah and prompts Manasseh to saw him in half (ch. 5). Belkira tries to get Isaiah to recant all which he has said about Manasseh, but of course the prophet refuses and his killed. He “spoke with the Holy Spirit until he was sawed in two” (14)