In confessing Christ as Lord, the Apostles’ Creed echoes the primary confession of faith of the apostolic church. The first creed was the simple statement, “Jesus is Lord.” The title Lord is the most exalted title given to Jesus. In the culture contemporary with the New Testament, the title kurios (“lord”) had various usages. It was sometimes merely a polite form of address, as in the greeting, “Dear sir.” It also designated a slave owner or master. The apostle Paul refers to himself as a “slave” (doulos) of the “Lord” (kurios) Jesus Christ. The slave lord purchased, owned, and governed his slaves. This connotation is used in a figurative sense frequently in the New Testament. The title lord was used in a more exalted sense to refer to those of imperial power and authority. The church faced a crisis when it was required to recite the formula Kyros Kaisar ("Caesar is Lord") in giving a loyalty oath to the emperor. The imperial title was filled with theological and religious connotations. Cullmann points out: “According to the ancient view, lordship over the world empire indicates lordship over the cosmos.” Hence many Christians chose to die rather than utter the loyalty oath. This refusal to call Caesar “lord” did not come out of revolutionary civil disobedience, but from reluctance to render to Caesar that which did not properly belong to him. Absolute authority, dominion, and power belonged to Christ, who alone reigns as cosmic Lord...
The Greek translation of the Old Testament (the Septuagint) used the term kurios to translate the Hebrew word Adonai, which was a title for God Himself. The Hebrew word Yahweh, which was the ineffable “name” of God, was too sacred to be used frivolously, even in worship. When a public reader came to Yahweh in the liturgy, the substitute word pronounced in its place was Adonai. Adonai was the title that indicated God’s absolute authority and power...
Psalm 8 begins in the NIV “O LORD, our Lord, how majestic is your name in all the earth!” A strict rendering from the Hebrew would be, “O Yahweh, our Adonai, how excellent. . . .” Yahweh is the “name” of God; Adonai is the “title” of God. This would be compared somewhat with the expression, President Woodrow Wilson. “Woodrow” was Wilson’s name; “President” was his title, which indicated his role or function...
That Jesus is objectively the Lord is a common assertion of the New Testament. He is the imperial authority of the entire creation. His authority has cosmic proportions. But the creed confesses not only that he is the Lord, but that he is our Lord. At the heart of the Christian faith is the believer’s personal submission to the authority of God’s exalted King. The confession is, in itself, meaningless. Jesus said, “Many will say to me on that day, ‘Lord, Lord, did we not prophesy in your name, and in your name drive out demons and perform many miracles?’ Then I will tell them plainly, ‘I never knew you. Away from me, you evildoers!’” (Matt. 7:22, 23). To say “Lord” and mean all that it implies cannot be done apart from the Holy Spirit.
(Sproul, R.. Renewing Your Mind : Basic Christian Beliefs You Need to Know. Grand Rapids: Baker Books)