December 18th "O"

O ADONAI, dux domus Israel,
qui Moysi in igne flammae rubi apparuisti, et in Sina legem dedisti:
veni ad redimendum nos in brachio extenso.

O Lord (Exodus 6:2, Vulgate), leader of the house of Israel,
who appeared to Moses in the fire of the burning bush (Exodus 3:2) and on Mount Sinai gave him the law (Exodus 20): come and free us with your powerful arm (Exodus 15:12-13).