This is more than a review. I cross-referenced the orations here with the sets in Schaff and Daley, so that you can see which ones overlap. This review will touch on both Gregory’s theology and the superb introduction by Nonna Harrison.
Noting how Gregory interweaves rhetoric, liturgy, and theology, Harrison summarizes:
(1) Festal anamnesis: these are re-presentations of God’s saving works in such a way that the worshiper “can participate in these events as present realities and receive the eschatological salvation” (Harrison 24). It is an “encounter with the Lord who transcends time.”
(2) Festal mimesis: similar to above, mimesis is a pattern of thought in which people sought to imitate the event (29).
On The Trinity
In an unusual move, Gregory speaks of the divine attributes as both singular and plural (Harrison, 38ff, Oration 23.11). Gregory is also insistent on the Cappadocian taxis: from the Father, through the Son, in the Holy Spirit.
Harrison then corrects the Schaff translation of periastraphthete, “struck from all sides by lightning.” Harrsion suggests this is important because “the divine persons surround Gregory’s congregation as three overwhelming lights that are also one light enveloping them” (40).
Gregory expertly ties in Christ’s birth as a reversal of the plague of darkness in Egypt and the darkness before Creation. Implying, among other things, that Egypt was a kind of reverse-creation (38.2).
The Format of the text
The anchor text for St Gregory of Nazianzus’s writings is volume seven of the Schaff series (NPNF 2). Does this work repeat the earlier work of Schaff? Yes, but it corrects the translations and the presentation is so much better that you should go ahead and get it.
Oration 1: On Pascha and His Slowness (Schaff-Gregory, p.203)
Oration 38: On the Nativity of Christ (Schaff-Gregory, p. 345).
Oration 39: On the Baptism of Christ (Schaff-Gregory, p. 352).
Oration 40: On Baptism (Schaff-Gregory, p. 360).
Oration 41: On Pentecost (Schaff-Gregory, p. 378).
Oration 45: The second oration on Easter (Schaff-Gregory, p. 422).