What does Matthew 12:8 mean?
Jesus concludes His rebuke of the Pharisees for their false accusation against His disciples (Matthew 12:1–2). The capstone of His response is a simple declaration.Jesus uses the phrase "Son of Man" throughout Matthew to describe Himself. His biggest problem with the Pharisees is they have failed to recognize Christ is the Messiah. This is something they refuse to acknowledge, despite witnessing so many of His miracles and hearing His teaching (John 5:39–40).
In this specific case, Jesus' critics have attempted to condemn His disciples, supposedly for breaking the command to keep the Sabbath (Exodus 20:8–11). The conflict, however, is really with the Pharisees' own false interpretation of the laws. This confusion would not have happened, had they understood Jesus to be the Son of God. God, of course, is Lord of all. He also holds priority over the Law. Jesus is saying, then, that in the end He is Lord even of the Sabbath.
It's important to see that Jesus is not giving Himself a blank check to break the Law of Moses. Jesus fulfilled the Law by keeping it perfectly. He is, however, declaring that He made the Sabbath and is the final judge of what it means to keep the Sabbath or not. He declares His disciples guiltless from breaking the Sabbath requirement by their simple act of plucking and eating grain.
Matthew 12:1–8 finds Jesus' hungry disciples breaking the heads off grain and eating as they walk through a field with Him on the way to the synagogue. Some Pharisees tell Jesus this is unlawful. In their interpretation, this is a violation of the command not to work on the Sabbath. Jesus counters the accusation with a series of questions, showing their manmade restriction cannot stand. Their legalistic, expanded view doesn't reflect God's intended meaning of the Sabbath. The Pharisees must learn that God desires mercy, not sacrifice. He declares Himself greater than the temple, and Lord of the Sabbath.
Matthew 12 features confrontations between the Pharisees and Jesus over several issues. Among these are working on the Sabbath, healing on the Sabbath, and the source of His power to cast out demons. Jesus counters each argument and rebukes the Pharisees sharply for their obstinate unbelief. He even notes that those who maliciously ascribe His miracles to demons are unforgivable. He warns them, and the rest of their current generation, about the judgment to come. Jesus calls the Pharisees a brood of vipers and rejects their demand for another miracle. All they'll be promised is the sign of Jonah. The Son of Man will be in the heart of the earth for three days. Jesus also states that all who do His Father's will are His family.