The early church was unanimous in its interpretation of this prophecy as a reference to Christ and the church. Theodoret, Cyril, Augustine, Gregory the Great, Eusebius, Jerome, and others all read these words from Isaiah and very clearly saw Jesus and his bride. Eusebius is representative of the Fathers and wrote this beautiful commentary, "One can take the time to learn in what manner the prophecies of the call of the Gentiles should be understood and that they were fulfilled only after the coming of our Savior. The beginning of the prophecy is consistent with the reality that the Lord descended not only for the salvation of the Jewish race but also for that of all people, in announcing to all peoples and all the inhabitants of the earth, 'Hear, all peoples, and let the earth and all in it listen'" (Eusebius, Proof of the Gospel).
While my Old Testament professors would cringe at this reading of the Old Testament which goes through the lens of Christ instead of spending most of our time trying to discern the 'authorial intent' of God's message to the original audience first, reading the Fathers has taught me otherwise. In fact, these great early theologians spent very little time, comparatively, unpacking the original intent and focused almost exclusively on a Christological understanding of the Old Testament. Many of the Church Fathers would fail contemporary Old Testament Introduction and Exegesis classes at conservative and liberal seminaries alike! Perhaps, and this suggestion requires a great dose of humility to consider, we are the ones who require corrective lenses, so to speak. Maybe our hermeneutics (i.e. our methods and ideas that guide our interpretation of Scripture) should be 'updated' to return to those interpreters who were closest to the source in time, language, culture, and understanding. Something to consider thoughtfully and prayerfully during this Advent season (and always).