O come, O come, great Lord of might,
who to thy tribes on Sinai’s height
in ancient times once gave the law
in cloud and majesty and awe.
Emmanuel shall come to thee, O Israel!
O Lord and Ruler of the House of Israel, who appeared to Moses in the flame of the burning bush and gave him the law on Sinai: Come and redeem us with outstretched arm.
Note: “Adonai” means simply “Lord” or “Master.” It was commonly substituted for the name of God YHWH, “I AM” (often rendered “LORD” in English translations), in order to avoid accidentally misusing His name.
Exodus, chapter 6:  But the LORD said to Moses, “Now you shall see what I will do to Pharaoh; for with a strong hand he will send them out, yea, with a strong hand he will drive them out of his land.”  And God said to Moses, “I am the LORD.  I appeared to Abraham, to Isaac, and to Jacob, as God Almighty, but by my name the LORD I did not make myself known to them.  I also established my covenant with them, to give them the land of Canaan, the land in which they dwelt as sojourners.  Moreover I have heard the groaning of the people of Israel whom the Egyptians hold in bondage and I have remembered my covenant.  Say therefore to the people of Israel, `I am the LORD, and I will bring you out from under the burdens of the Egyptians, and I will deliver you from their bondage, and I will redeem you with an outstretched arm and with great acts of judgment,  and I will take you for my people, and I will be your God; and you shall know that I am the LORD your God, who has brought you out from under the burdens of the Egyptians.  And I will bring you into the land which I swore to give to Abraham, to Isaac, and to Jacob; I will give it to you for a possession. I am the LORD.'”
(Revised Standard Version)