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.