Christ's Lordship Also Means His Ownership
The purpose of the Old Testament quotations that Paul uses in Romans 10:6-7 is to explain the nature of the righteousness that is by faith. In the Old Testament, the 'word' was the Law of Moses. But Paul applies these concepts to the gospel: righteousness has been brought to sinners by a Christ that is near and available to both Jew and Gentile. English minister and Bible commentator Matthew Henry (1662-1714) says:
The self-condemned sinner need not perplex himself how this righteousness may be found. When we speak of looking upon Christ, and receiving, and feeding upon him, it is not Christ in heaven, nor Christ in the deep, that we mean; but Christ in the promise, Christ offered in the word. Justification by faith in Christ is a plain doctrine. It is unbelief. If a man confessed faith in Jesus, as the Lord and Savior of lost sinners, and really believed in his heart that God had raised him from the dead, thus showing that he had accepted the atonement, he should be saved by the righteousness of Christ, imputed to him through faith. But no faith is justifying which is not powerful in sanctifying the heart and regulating all its affections by the love of Christ. We must devote and give up to God our souls and our bodies: our souls in believing with the heart, and our bodies in confessing with the mouth. The believer shall never have cause to repent his confident trust in the Lord Jesus.
People who confess Christ's lordship confess his ownership as well. Confessing with our mouths that Jesus is 'Lord' is recognition of God's possession and power over all things. For the Romans, this confession meant recognizing Jesus as God, equal with the Father and deserving of all honor, and perhaps just as important, his opposition to any other authorities claiming the same (such as Caesar). Social activist and author Jim Wallis points out that the early Christians were accused of 'atheism' because of their allegiance to Jesus Christ rather than to the emperor whom the Romans deified.
In the days of the early church, the Christians were often accused of being atheists. Their love for the Lord, the fervor of their worship, and their fidelity to Jesus Christ were so clear, public, and unmistakable that they were charged with being atheists in regard to the false gods that rule the Roman world. The central affirmation of the early Christians was 'Jesus is Lord.' They knew and the authorities knew what that meant. Their worship was understood politically by the authorities, and they were treated accordingly. If Jesus was Lord, then Caesar was not. If Jesus is Lord, then neither mammon nor the nation is the object of worship. If Jesus is Lord, then his disciples have no other lords. In short, worship expresses to whom we belong.