Jesus Christ is Lord
Romans 10:9 - If you confess with your mouth the Lord Jesus and believe in your heart that God has raised Him from the dead, you will be saved.
The term "Lord" is sometimes used in Scripture simply as a title of respect, as we might say "Sir". However, it would be a serious mistake to assume that that is always the sense of the word, especially when used of Jesus Christ. The Greek word which is most often translated "Lord" is kurios. Kurios refers to one who has legal power or one who possesses authority over others. The Bible speaks of God as the Lord — the One Who has absolute power and authority over every aspect of creation, including human beings. When Jesus is called "Lord" it is an affirmation of His Deity and as such an affirmation of His authority over mankind.
The message of the early church to the Hebrew community which had crucified Jesus as a blasphemer was this: "...let all the house of Israel know assuredly that God has made this Jesus, whom you crucified, both Lord and Christ". That truth was verified by the resurrection of Jesus from the dead and by the giving of the Holy Spirit to the church. The marvelous reality that the Jesus, whom they had known so intimately for three years and had seen die the horrible death of the cross, had been raised from the dead and had ascended into Heaven as the Lord strengthened the Apostles to do heroic deeds for the Gospel. Those men were on the scene and had been so frightened for their own safety that they retreated from public sight. Yet, now the evidence for the exalted triumph of Christ was so compelling that they were willing to risk suffering, imprisonment, and even death in His service. Their conviction was that He ruled and that He would take care of them.
The conclusion must be that any true faith in Jesus must be a faith which embraces Him both as the Redeemer Who put away sin by the sacrifice of Himself and as the Lord Who rules over the universe and Who must be obeyed by all who follow Him. The idea that one can have a personal relationship with Christ while refusing to acknowledge His right to direct that individual's life by the counsel of His Word, is actually a denial of Who Christ is. Faith in Christ is at its core a voluntary submission to Him as God and Master—Owner and Proprietor of all things.
The practical impact of this is that people who claim to be followers of Christ and yet are indifferent to the will of Christ expressed in the Scriptures are playing games with Christ and with themselves. They do not know Who Christ is. They have not been brought face-to-face with awesome glory and majesty of the One Whose Name is above every name and before Whom every knee will one day bow and every tongue confess that He is Lord over all lords and King over all kings.