The second O Antiphon is to Adonai (Lord).
O Adonai, et dux domus Israel,
qui Moysi in igne flammae rubi apparuisti,
et ei in Sina legem dedisti:
veni ad redimendum nos in brachio extento.
O Lord, and leader of the house of Israel,
who appeared to Moses in the fire of the burning bush,
and gave him the Law on Sinai:
come to ransom us with outstretched arm.
In this antiphon, Christ is addressed as God of Israel, the Old Testament Adonai himself. Like the previous antiphon, it depicts Christ in his divinity.
But whereas the mystery of Christ Sophia is manifest in all creation, Christ Adonai is revealed in history. Christ Adonai is the Son in the unity of the Godhead, but also the particular god of Israel, shepherd of his people, lord and lawgiver. He is He-Who-Is, YHWH, and one whose “outstretched arm” is mighty to redeem.
This antiphon celebrates the second stage of revelation, when the source of all being gave Israel his name in the burning bush, and the Law in a cloud of glory on Sinai.
The choice of these two examples is significant. Christian tradition has seen the burning bush as a sign of the incarnation in several ways. First, Moses met the Son in the burning bush. The text indicates that “the angel of the Lord”–whom the Church Fathers almost universally identified as the Logos/Christ–was he who appeared in the flames.
Second, the union of the living flame with the living bush was thought to signify the union of divinity and humanity in Christ.
Third, an ancient tradition that survives in both Eastern Orthodoxy and Catholicism affirms that the Burning Bush prefigures the Virgin Mary, on whom the divine light descended without causing her harm or loss of virginity.
The giving of the Law to Moses is also a moment full of Christological significance. Adonai came down on Sinai in lightning and smoke and thunder. The meeting of God and Moses produced stone tablets on which were written divine commandments, and Moses carried the Law down to Israel godlike in appearance. Around this time, possibly on Sinai, Moses asked for a more perfect vision of the glory of God. Nevertheless, he was permitted to see only the “back parts” of God, from a cleft in the rock.
As St. Irenaeus pointed out, at the transfiguration of Christ on Tabor, God finally gave Moses the fullness of his original request: Moses saw the face of his Lord. Sinai thus prefigures Tabor, where the Word conversed with Moses and another prophet who met God on a mountaintop. In this moment, Christ revealed himself as the completion of Law and Prophets.
Moses in the Rock (2011), by Jack Baumgartner
Transfiguration Icon from Sinai
The primary message for Christmas I see in O Adonai is that Christ does not come to Israel as a divine foreigner, but as Israel’s own god, who gave the people the Law in the first place. He is fulfilling the promises of redemption he himself made.
This is easily forgotten with the incarnation. We think of Adonai as the severe and just Father who sent his son to die for us. But the truth is that the Son shares all the qualities of his father. The Son was present in flames in the burning bush, and in the pillar of fire and cloud that led the Israelites through the wilderness. It was he whom Abraham welcomed, and he whom the prophets acclaimed.
And it is he who, truly, has tabernacled among us in the flesh.