O Lord — December 18

O Adonai, et Dux domus Israel, qui Moysi in igne flammæ rubi apparuisti, et ei in Sina legem dedisti: veni ad redimendum nos in brachio extento.

http://www.youtube.com/watch?v=o6y9Idko8-A&feature=channel_page

O sacred Lord of ancient Israel, who showed yourself to Moses in the burning bush, who gave him the holy law on Sinai mountain: come, stretch out your mighty hand to set us free. — translation in current Catholic Liturgy of the Hours

O come, O come, thou Lord of might / Who to thy tribes on Sinai's height / In ancient times didst give the law / In cloud and majesty and awe. — Verse translation in "O Come, O Come, Emmanuel"

Adonai — Lord — Exodus 3:14-15 (Adonai is substituted for YHWH when the scriptures are read aloud, as the actual name is not to be pronounced in Jewish tradition)

in igne flammæ rubi apparuisti — appeared in the flame of the burning bush — Exodus 3:1-6

ei in Sina legem dedisti — gave him the law on Sinai — Exodus 19:16-20:17

in brachio extento — with outstretched arm — Deuteronomy 26:8