The Messiah and the Lord that Fulfills, Matthew 22:34-46

In this final confrontation with the Pharisees before his trial and crucifixion, Jesus answers a final question about the greatest commandment. He then quickly turns the tables on his questioners with a question about how the Messiah can be both the son of David and his Lord. How are these two moments connected? What does this mean for us who are unable to keep the commandments?

Image: Jesus with the Pharisees, by Jacques Callot, public domain. Image location: https://www.nga.gov/collection/art-object-page.33324.html