Mark 12:35-37
"David himself calls him Lord. So how is he his son?” And the great throng heard him gladly. (Mark 12:37 ESV)
Jesus was teaching about the Messiah to a group of Jews. While teaching he pointed out that David himself recorded a prayer to the Messiah, calling him Lord. This was all done as part of a teaching about the diving lineage and human royal heritage of the promised Messiah. But Jesus' recalling of David's words make an incredibly powerful point.
King David stands out in history as one of the most influential leaders the world has ever known. The leadership he characterized among his people changed the course of their nation so profoundly that even today the Jewish national emblem is called the "Star of David." Jesus' point in bringing up David, however, was that the Messiah would be even more important. While David was a very kingly kind of king, Jesus Christ is the King of kings.
Lordship is an interesting thing. Often it is a foreign concept in our modern western culture. We are far removed from the feudal days of lordly landowners and fealty. But e Lordship of Christ is larger than that anyways. Jesus, as Lord, is one who we can and should serve. And the real kicker is that he considered our service to himself important enough that he died for us. His death paved the way for our service. He served humanity so that humanity could serve him.
King David wrote about Messiah, calling him Lord. The disciples came to know Jesus as Lord and went on to change their whole world. One day every person that has ever lived will acknowledge him as Lord. He is Lord.
That all sounds very theologically astute, but what does it mean for us today? It means that there is value in service to God. It means that a life lived in pursuit of God is not a wasted life. Living the God-life, calling Jesus Lord, there is great fulfillment in that.