Day 2 of the O Antiphons is O Adonai
God made a Covenant, first with Adam and Seth, then with Noah and Shem (Melchizedek) and then again with Abraham and Isaac. Each Covenant made with the father for the son was a Covenant of family. In changing Abram’s name from ‘Father of a nation’ to Abraham, ‘father of many nations’ God pointed us towards the next Covenant where he would change Jacob to Israel and make a national covenant with him and later Moses with a promise of an International Covenant that would come when all Israel was saved by Christ. All these covenants are about God giving Himself to the family and then the nation of Israel in which He is the Beloved husband/Bridegroom and Israel/Jerusalem is the bride. This was a prefiguring of Christ the Bridegroom who would pour Himself out for His Bride the Church.; the new Israel.
In those days woman would call their husbands adonai, beloved husband. But a concubine like Hagar or Jacob-Israel’s concubines Bilhah and Zilpah would call their “husbands” ba’al meaning master-husband.
When Israel worshipped God their beloved they could call Him Adonai. When they worshipped the gods that made them slaves they worshipped Ba’al and his consort Asherah. God called them on it and called them back to Him “And you shall be My people, and I will be your God.” He said.
God does not makes us slaves. He loves us and gives himself to us. So a Covenant is an exchange of persons, as you get in the Sacrament of marriage, whereas a contract is an exchange of things. If all we have with God is some kind of contract then we are little better than slave-concubines. We must love Him as He loves us and then we can call on Him “O Adonai!”