For a general introduction to Eusebius, please see the commentary on Ecclesiastical History I.6.6-11.

Until the 2013 English translation of Jonathan Armstrong, used above, Eusebius’s Commentary on Isaiah had not been available in full in a modern language, despite it being the first Christian commentary on the book of Isaiah to have survived to the present day (Jonathan Armstrong and Joel Elowky, Commentary on Isaiah, p. xxi). However, the text is an extremely important example of patristic exegesis, and contributes significantly towards our understanding of Eusebius’s thinking on various topics. Significantly for our purposes, Eusebius’s attitude towards the Roman empire is one of these, and as we shall see below, the commentary shows a slightly different approach towards the empire and the emperor to that which we see particularly in his panegyrical writings to Constantine. The date of the commentary has been debated, but scholars have tended to agree that it is post-Nicene (so post-325 CE), due to the fact that Eusebius’s worldview is generally positive about the future, indicative of a compositional date under the Christian emperor Constantine that Eusebius so admired (so, for example, Charles Kannengiesser, Handbook, p. 677). Adolf von Harnack, and various scholars after him, such as David Wallace-Hadrill, argue that because the commentary discusses persecution as something past (for instance at 44.5), it cannot have been written prior to 324 CE (Harnack, Geschichte, Vol 2.2, p. 123; Wallace-Hadrill, Eusebius of Caesarea, p. 32; between 323 and 325 CE is suggested by Jean Marie van Cangh, “Nouveaux fragments,” p. 384-390). Timothy Barnes prefers slightly later, around 330 CE (Constantine and Eusebius, p. 278). As Michael Hollerich explains, the commentary references Eusebius’s Chronicle, Onomasticon, and the Martyrs of Palestine indirectly, the second of which (in 18.2 of the commentary) might be helpful for dating the commentary. Wallace-Hadrill dated the Onomasticon to 326-330 CE, which would suggest a date in the 330s. However, Barnes has proposed that the Onomasticon cannot be later than 327 CE, which if correct would mean that a date for the Commentary on Isaiah closer to the Council of Nicaea is more likely (see Wallace-Hadrill, Eusebius of Caesarea, p. 55-56; Barnes, Constantine and Eusebius, p. 228, 386, n. 29; Barnes has actually suggested that the Onomasticon is one of Eusebius’s earliest works, possibly written in the 290s CE, and as Hollerich states, if this is correct, it is less useful for dating the commentary; Barnes, “The Composition,” p. 412-415; Hollerich, Commentary on Isaiah, p. 21; Barnes’s argument is contested by Andrew Louth, “The Date,” p. 118-120). Hollerich looks to the attitude towards imperialism that Eusebius shows in the Commentary on Isaiah in order to help date the text, and highlights the fact that the empire is presented as adherent to Christianity, which is unlikely before Constantine’s defeat of Licinius in 324 CE. For instance, in 49:23, there appears to be a reference to a distribution of grain to the poor of the church by Constantine, which Eusebius mentions in the Life of Constantine IV.28 (for a more detailed discussion, and further arguments for a dating shortly after Nicaea, see Hollerich, Commentary on Isaiah, p. 21-26).

Hollerich identifies the commentary’s exegetical theme as focused on the “godly polity” (τό θεοσεβής πολίτευμα, to theosebēs politeuma), which Eusebius sees as having undergone several phases: a Jewish phase, a transferral to Christianity, propagation throughout the world, and finally an apotheosis in heaven. Eusebius aims at making clear the Church’s claim to Isaiah over and against that of the Jews, and the superiority of Christianity over Judaism, suggested here in the present passage (see Hollerich, Commentary on Isaiah, p. 26). While the commentary stems from the same period as Eusebius’s Life of Constantine and his panegyrical speeches, when Constantine enjoyed sole rule of the Roman empire and the Church enjoyed his patronage, Eusebius’s tone here is noticeably different from these other works. Rather than prioritising praise of the emperor and the Christianised Roman state, the Church as an “ecclesiastical community” takes centre stage. Granted, the empire is now ruled by a Christian princeps, but in the Commentary on Isaiah as a whole Eusebius does not present the Church as “merely the religious arm of a Christian state” led by the emperor, but rather a community led by bishops such as himself (Hollerich, Commentary on Isaiah, p. 30-31, quotations at p. 31). The emperor is a Christian who performs important functions for the church, such as giving donations to the poor and suppressing pagan cults, as well as attending liturgical services like other Christians. The Church is a “polity” (an organised body of Christian “citizens”) cared for by the bishops and their subordinates, and Hollerich sees it as possible that this presentation is aimed at present or future clergy who needed to be reminded of their prominent roles. Essentially, he argues, Eusebius wanted to show how the godly polity was revealed in the fulfilment of events that the prophet Isaiah foretold. The commentary therefore offers biblical reinforcement of the Church’s group identity after the Council of Nicaea, where the Church is not viewed as a rival to the empire, but is superior to it in the sense that it is God’s true focus for his activity. The empire is an important part of God’s plan, but is ultimately of secondary importance (Hollerich, Commentary on Isaiah, p. 32-33). Indeed, one of the functions which the empire performs is the punishment of the Jewish people, and this will be discussed in relation to the present passage further below. We see in the commentary the apologetic themes that are present elsewhere in Eusebius’s writings, such as the notion that Christ’s incarnation coincided with the Pax Romana. However, missing is the presentation of the emperor and his reign as patterned on the monotheistic kingdom of God (see, for instance, In Praise of Constantine III.3-5). Hollerich argues that this is because this ideal somewhat clashed with Eusebius’s emphasis on the bishops as the leaders of the godly polity (the Church), and he does not want Constantine to steal the limelight of the bishops as God’s earthly representatives of Christ’s glory. Accordingly, Constantine is not mentioned by name in the commentary, despite there being several allusions to him and his reign (Hollerich, Commentary on Isaiah, p. 194).

The theme of the superiority of Christianity over Judaism in the commentary follows on from Eusebius’s earlier development of the same in his Proof of the Gospel, and can also be seen elsewhere, for instance in his Ecclesiastical History I.6.6-11. As Armstrong notes, in the commentary, Christianity’s claim over Judaism is primarily in terms of superior scriptural interpretation. However, it must be remembered, as Brevard Childs has highlighted, that there is emphasis on the universalism of Isaiah’s message for all the nations, not just Gentiles or Jews specifically (see Armstrong and Elowky, Commentary on Isaiah, p. xxxiv; Childs, The Struggle, p. 85). For Hollerich, this agenda might reflect Eusebius’s perceived need to re-emphasise the boundaries between Christianity and Judaism for the new Christian emperor’s benefit. He draws on evidence that Constantine quickly picked up on the animosity towards the Jews among Christians, such as the emperor’s letter to the churches after the Council of Nicaea, which is preserved in Eusebius’s Life of Constantine III.17.1. The letter is concerned with fixing the date of Easter, and the main problem is that some Christians are relying of the Jewish Passover to determine this. Constantine, according to Eusebius, claims that the Jews are ignorant and mad due to their part in the crucifixion, and Christians therefore ought not to associate with them. Constantine’s attitude towards the Jews is also hinted at in his legislation, which seems to seek to limit conversion to Judaism (the situation is far from clear cut, however, and for a detailed discussion of the surrounding debate see the commentary on Life of Constantine IV.27, which describes the emperor’s forbidding of Jews owning Christian slaves) (Hollerich, Commentary on Isaiah, p. 33-35). The other point to note in relation to the specifics of our passage is that whenever the Roman empire is mentioned in the commentary, it is generally in reference to the events of 70 CE (the destruction of the Jerusalem Temple) or 135 CE (the quashing of the Bar Kokhba Revolt), when the Roman emperors acted as deliverers of divine punishment to the Jewish people. Moreover, Hollerich notes that if Eusebius had wanted to utilise it, the book of Isaiah provides the ideal opportunity for a comparison between Constantine and the Persian king Cyrus, who allowed the rebuilding of the Jerusalem temple around 539 BCE, and whom the Book of Isaiah describes as God’s anointed (cf. Isaiah 45:1-3). However, the passages related to Cyrus are instead interpreted historically (Hollerich, Commentary on Isaiah, p. 195). Ultimately, the Roman empire is nowhere near as prominent in the commentary as in other texts—it is primarily discussed in so far as it serves the needs of the Church. Eusebius’s attitude can therefore be seen to be different from other works where he is keener to praise the Christian emperor. Here, he is primarily Eusebius the bishop.

In the passage quoted above, Eusebius addresses the failure of the Jewish people to accept Christ as the messiah (on this theme see also 10:12-18), and joins numerous other sections of the commentary in interpreting Jewish defeat at the hands of Vespasian and Hadrian through this lens (see also 1:5-6, 2, 31; 2:6-9; 5:11-17, 25-30; 6:3-4, 11-13; 17:9-11; 27:12-13; 29:3, 5-8; 34:9-10; 51:17-19; for the references, Hollerich, “Eusebius as a Polemical Interpreter,” p. 599). That the Romans acted either as God’s punishers of the Jews or at least served to end their period of God-given independence, and pave the way for the Christian era was a popular theme among early Christians, and one which Eusebius himself has previously treated, for example in his Ecclesiastical History I.6.6-11. In the extract quoted above, the words of Isaiah 1:20 are interpreted as prophesying the disobedience and disbelief of the Jews, who failed to accept God’s chosen messiah. That which is promised by the Word at the opening of the passage refers to Isaiah 1:19: “If you are willing and obedient, you shall eat the good of the land” (NRSV). The punishment for the Jewish people’s disobedience is their “devouring” (κατέδω, katedō) by a sword/dagger (μάχαιρα, machaira), which Eusebius interprets accordingly as the swords of the Roman army, who are described as conquering the Jews according to “the law of war” (πολέμου τε νόμῳ, polemou te nomō). The same phrase is also employed by Eusebius elsewhere. For example, in his description of the Bar Kokhba Revolt in his Ecclesiastical History IV.6.1, he states:

“He (Rufus, the governor of Judea) destroyed in heaps and thousands hundreds of men, women and children, and, under the law of war, enslaved their land” (Loeb translation by Kirsopp Lake, p. 313).

In the Theophany IV.18, Eusebius describes the destruction of the Jerusalem Temple as follows:

“And it was right, not only that the inhabitants of the city, but also the land itself— in which they so greatly boasted—should be made to suffer the things, which the deeds of its inhabitants deserved. And these they did suffer! For it was not long, before the Romans came against the city: and, of the inhabitants, some they killed by the law of war; others they destroyed by famine; others they led away captive; and others they persecuted” (translation by Samuel Lee, freely available here: http://www.tertullian.org/fathers/eusebius_theophania_01preface.htm).

In the Life of Constantine II.10 and II.18, the phrase is used in Eusebius’s account of the battle between Constantine and Licinius, and the aftermath of this event:

 “On this they immediately turned and betook themselves to flight; and some were overtaken and slain according to the laws of war, while others fell on each other in the confusion of their flight, and perished by the swords of their comrades” (II.10)

“He then proceeded to deal with this adversary of God and his followers according to the laws of war, and consign them to fitting punishment” (II.18) (translations by Ernest Cushing Richardson, freely available here: https://sourcebooks.fordham.edu/basis/vita-constantine.asp).

In these passages, Eusebius clearly refers to the common rules of warfare, whereby in addition to mass casualties, the defeated are subject to enslavements and loss of land at the hands of their enemies. Eusebius makes clear that in each case, the deaths and other punishments of the defeated were acceptable in the framework of battle. This was perhaps particularly important to emphasise in relation to Constantine’s battles with Licinius, who is presented as an enemy of God. Eusebius ensures that Constantine’s actions are not painted as excessive and cruel, but perfectly legal and justified, especially given the impiety of his adversary. Granted, from Cicero’s time onwards the concept of the “just war” was part of Roman tradition, and conceived of as one which was waged for defence of one’s people or honour. Wars without provocation were classified as unjust (see the commentaries on Caesar, The Gallic War I.36 and Caesar, The Gallic War I.45). Understood within this framework, the Roman suppression of the revolting Jews would certainly be justified in Eusebius’s eyes; the “laws of war” applied in that it was not simply a case of the Romans slaughtering the Jewish people for no reason. However, his interpretation of these events in the present passage (as elsewhere) is deeper than this; the Romans are not merely acting according to the accepted laws of war, but are doing God’s will, punishing his wayward people. The deservedness of the fate of the Jewish people is re-emphasised in the final sentence of the passage, where Eusebius re-states that it was their rejection of Christ which condemned them. Of course, these conflicts between the Jews and the Romans were events of the distant past by the time Eusebius was writing in the fourth century. However, it is interesting to consider his attitude in relation to the Christianised empire that he composed his Commentary on Isaiah within (along with numerous of his other writings). As we have seen above, the notion of acceptable “laws of war” was something which Eusebius appealed to time and again in his descriptions of the conflicts between both the Romans and the Jews and Constantine and his enemies. In both cases, he understood the deaths and other punishments of the defeated as deserved. Moreover, it was God’s will that these defeats occurred, as both the Jews and Constantine’s enemies had not accepted Christ and/or stood in the way of the spreading of the divinely-sanctioned Christian rulership of Constantine. Indeed, as George Demacopoulos argues, particularly in Eusebius’s descriptions of Constantine’s wars, Eusebius had to embrace the violence of the emperor’s reign insofar as it was serving to spread Christianity and suppress those who were opposed to God. Eusebius therefore needed to paint Roman violence positively, and his method was to highlight “the potential for violence to be a vehicle of God’s action in history” (“The Eusebian Valorization,” p. 120-121, quotation at p. 121).

The present passage from the Commentary on Isaiah draws on a dominant theme which we see elsewhere in Eusebius, namely the rightful punishment of the Jews at Roman hands, and in this sense is not new. Moreover, as discussed in the introduction above, this text differs from several of his other prominent works in that Eusebius is not primarily seeking to valorise the Roman empire or its Christian emperor. Rather, the focus is the Church and the bishops who preside over it, along with the re-affirmation of Christianity’s superiority over Judaism. The words of Isaiah 1:20 are therefore naturally interpreted as predicting Rome’s conquering of the Jews, God’s vindication for his people’s failure to accept Christ. Moreover, as we have seen, the language used to describe these events, which echoes that employed in several other descriptions of battles by Eusebius, not only reflects the author’s understanding of the rightful outcomes of these events, but also highlights the fact that as the empire came to be headed by a Christian emperor the Christian bishop needed to justify the empire’s violent actions. That both Constantine’s wars and those of his predecessors against the Jews were both conducted according to the “laws of war” implies the divine sanction of both.