What does Luke 5:17 mean?
Jesus is teaching a large group of people in His home in Capernaum (Mark 2:1). Although Luke already recorded the conflict Jesus experienced in His hometown (Luke 4:16–30), this is the first time he mentions antagonism between Jesus and the religious leaders, specifically Pharisees and scribes.Judaism included several sects including Pharisees, Sadducees, Zealots, and Essenes. Pharisees set themselves apart by strictly following the Mosaic law as well as the extra regulations found in the Oral Law, what we have now as the Mishnah. Jesus struggles with the Pharisees throughout His ministry; He praises their dedication to holiness (Matthew 5:20) but condemns the unscriptural burdens they place on people (Luke 11:46). The Pharisees, in turn, condemn Jesus' rejection of their traditions, including what they consider to be judicious regulations about the Sabbath (Luke 6:1–11), fasting (Luke 5:33–39), and unclean eating practices (Luke 5:29–32; Matthew 15:1–2). "Teachers of the Law" are scribes (Mark 2:6), lawyers of the Mosaic law who maintain and debate the Oral Law. Scribes can be of any sect; these happen to be Pharisees.
After Jesus had healed the man with leprosy, He told him to go to Jerusalem and talk to the priests (Luke 5:14). The priests are mostly Sadducees and follow the Scriptures but not the Oral Law. They should be able to recognize Jesus, who can heal leprosy and make people clean, as being empowered by God. As the religious leaders with the most authority and prestige, they should set the tone for the nation and lead the people in following Jesus.
But the man healed of leprosy didn't go to Jerusalem. He spread the news around Galilee (Mark 1:45) and drew the attention of judgmental legalists from all over the Jewish territories. The Pharisees should have understood that a man with divine power to make another man ceremonially clean also has authority to declare sins forgiven (Luke 5:21). Yet the Pharisees only see a threat to their control over the people.
"Lord" is from the Greek root word kyriou. In general, it means "master," but in the New Testament most often refers to Jesus as an authority figure. This phrase could be misunderstood to suggest that Jesus is not God, or that God is giving power to the man Jesus. That's not the purpose of the statement; this is not a definition of Jesus' nature. Rather, this introduces the miracle He is about to accomplish and asserts that this is God-power, not coming from any other source. At another time, Jesus has a much longer conversation about this with the Pharisees from Jerusalem (Mark 3:22–30), which Luke also mentions (Luke 12:10).
"On one of those days" literally means "as it happened," Or "as it came to pass." It refers to one of the days Jesus was teaching and acts as a general introduction without the commitment of a specific time frame.