Eusebius (ca. 260-340 A.D.), is of course best known for his work Ecclesiastical History for which he came to be dubbed the ‘father of church history’. It is only in more recent decades that research has focused more on Eusebius as a Biblical commentator, and still more recently his Isaiah commentary has been unearthed, analyzed and made available (1999). It is clear enough that Eusebius is cognizant of earlier approaches to interpreting the Bible in the Christian tradition, but his teacher was taught by Origen, and so he does indeed stand in the line of the Alexandrian exegetes though he lived in Caesarea Maritima in the Holy Land, and was bishop there. He, like Origen, is concerned with various Greek translations of Isaiah, and textual variants, and he does not think that the deep meaning of the Biblical text necessarily lies right on the surface of the text. He is supercessionist and apologetic in his interpretation of Isaiah, wanting to demonstrate that it was prophesied all along that the church was to be God’s people, though he concedes that before Christ there were faithful Jews who were God’s people. While Jerome was later to accuse Eusebius of lapsing into allegory like Origen, in fact Eusebius focuses on two sorts of senses he found in the Biblical text—literal and spiritual, and sometimes they were intertwined. Childs thinks that Eusebius saw the spiritual sense as a metaphorical extension of the literal sense.
Eusebius uses the whole of Isaiah to present the Gospel, with texts being applied to everything from the virginal conception (Is. 7.14 of course), to the death and resurrection (Is. 52-53 of course), to the return of Christ and the kingdom come fully on earth (Is. 62-66). We will focus on his interpretation of Is. 7.14 for a moment. He is well aware of the Jewish rebuttal of the Christian interpretation of the text, namely that it refers to an ordinary birth of Hezekiah. He responds: 1) that the LXX translators knew what they were doing when they used parthenos which is more technical than ‘young nubile woman’ (neanis) and anyway Deut. 22.27 shows that even the latter word could mean ‘virgin’; 2) that a normal birth is hardly a ‘sign’ but Isaiah calls it that; 3) Immanuel can hardly be Hezekiah since he was already sixteen when Ahaz began to reign. Whereas Prophetic Selections works its way through Isaiah, interpreting in a Christian manner, Proof of the Gospel sets up theological categories and slots texts into them, providing proof-texts for a Biblical theology. “Eusebius chooses to concentrate on chapters 6,7,8, and 9, which he immediately sets within the context of John’s prologue in chapter 1 and he continues to weave his Isaiah texts with New Testament citations to produce a sort of ‘biblical theology’ of the Incarnation.” In other words, Eusebius is indeed ‘reading backwards’. He starts with John 12.41 which says Isaiah saw Christ glory, and says this (described in Is. 6) with the guidance of the Spirit is what led Isaiah to prophesy Christ’s birth from a virgin, and also in Is.6 the hardening of the Jews, which includes the continual opposition by Jews to the Gospel in the church age. Eusebius also sees a perfect and literal fit between Is. 35 and the ministry of Jesus in which the blind did really receive their sight, as well as a literal fit between Jesus’ birth in Bethlehem and what Is. 9 and 11 say (with help from Micah 5 and Ps. 132).
Eusebius interprets the stump of Is. 11 to refer to the dead end destiny of the race of David, whereas the shoot of Jesse is a reference to Jesus, humble and poor but equipped with wisdom, understanding and might to rule. Interestingly, in his treatment of Is. 35 in the Isaiah commentary he focuses less on Jesus as a healer, and instead sees the church’s baptism as the bath of regeneration transforming the land. And yet, Eusebius is apparently the first Christian writer to treat the Cyrus prophecy in Is. 44-45 at length in a historical manner (though there are scattered hints in Origen) over against Barnabas, Irenaeus and Tertullian who read ‘to Christ my Lord’ rather than ‘to Cyrus’. Eusebius repeats the legend found in Josephus Ant. 11.1-7 that Cyrus knew the prophecy of Isaiah because it was shown to him by Jews. Interestingly, Eusebius spends much time pondering the Incarnation on the basis of Isaiah, for example he joins Is. 61.1 to 60.22b and sees a reference to the two natures of Christ, one referring to ‘the Lord’ (i.e. the divine side of who he was) and the other to the recipient of the Spirit, and so he interprets Luke’s use of Is. 61 in Lk. 4.16ff. to refer to the divine anointing of Jesus by the Spirit.