The BASIC truth of Jesus Christ being LORD is the fact that He is God Himself who created the world and everything in it. Not only that, but He sustains and controls all things too. He is the only way of salvation and that way is described in the gospel of grace, which identifies Him as the God-appointed God-Man Mediator who accomplished Redemption by establishing an everlasting righteousness whereby God's elect will be justified by. This is done without works or conditions on their part but wholly by the free and sovereign grace of God alone.
For His sheep He is THE LORD OUR RIGHTEOUSNESS (Jer 23:6). That is one of His names. Since believers (also called His "church" or "bride") are said to be dead to the law and married to Christ, they take on His name - THE LORD OUR RIGHTEOUSNESS (Jer 33:16). Makes perfect sense since their righteousness came from Him as they were MADE righteous by the Father freely charging (imputing, legally transferring or reckoning) them with His righteousness, justifying them freely forever. This is real Lordship Salvation. His sheep love and serve Him because He first loved them