What do we mean when we declare that "Jesus is Lord"? Though it was a common title used by the early Christians it is not often used in the gospel of Mark to illuminate Jesus' identity. However, in one key passage, Mark 12, Jesus cites Psalm 110 and indicates the title is essential to grappling with His identity. Jesus' argument is the Lord must be both the master (the one who we obey) and God Himself. This passage is the clearest claim to divinity Jesus makes in the gospel.