Jesus’s description of his disciples as his brothers and sisters serves as the conclusion to the conflict stories in Matthew 8-12 and a segue into the Parables of the Kingdom in Matthew 13. Jesus’s true family are those who do the will of the father. This stands in contrast to the Pharisees who declare Jesus casts out demons by the power of Beelzebul. The Pharisees are given the sign of Jonah and in the last days they will be judged by the people of Nineveh and the Queen of the south.
Differences from Mark 3:20-21
Matthew does not include an important detail found in Mark 3:20-21. His family heard about the huge crowds and they came to “take charge of him” because they thought he was out of his mind. Following this the teachers of the law declare Jesus is casting out demons by the power of Beelzebub (3:22-30) and Jesus’s mother and brothers come to take him home (3:31-35).
Another key difference is Mark does not mention the disciples (those sitting around him). Matthew specifically states it is the disciples who are the ones doing his will. In both Matthew and Mark, the next section begins with the Parable of the Sower (Mark 4:1-20; Matthew 13:1-23).
Jesus’s Brothers Do Not Believe
That Mary should have some doubts is surprising for most readers. Although in Luke’s version of the story, an angel appeared to her and explains her son will be the “Son of God” (Luke 1:35). In Luke 2:22-37 Simeon and Anna recognized her child as the messiah. It may be the case she had some doubts because Jesus does not appear to be interested in taking the throne of his father David or reigning over the house of Jacob (Luke 1:32-33).
Where is Joseph? He would be thirty years older than Jesus at the least. If Joseph was even twenty when Jesus was born, he would be on the high end of the average life expectancy for a hard laboring peasant in the first century world. In some traditions Joseph was considerably older than Mary, making his death by this time more likely.
That Jesus has brothers is no surprise to Protestants, it is only a problem for Roman Catholics who believe in perpetual virginity of Mary. These must be cousins of Jesus or Joseph’s children from a prior marriage. The unbelief of Jesus’s brothers is more prominent in John’s gospel (John 7:1-5).
Why do Jesus’s brothers not believe Jesus is the Messiah? John 7 implies they have seen some of his signs yet still do not believe. They may not believe for the same reason as the Pharisees, Jesus may be doing messianic signs, but he is not doing the commonly expected messianic acts. Jesus does not seem interested in an earthy kingdom. He is not acting like David, Solomon, or even Judas Maccabees. In the next chapter Jesus will describe what he means by the kingdom of heaven through a series of parables. He calls this “the mysteries of the kingdom of heaven” because his kingdom is in many ways radically different than Jewish messianic expectations in the first century.
Pointing to his disciples, Jesus declares his family are those who do the will of the Father (12:49-50). What is “doing the will of the Father”? Jesus as the son of God does what the Father commands, the disciples are the insiders who hear what the Father commands and respond proper.
By opposing Jesus, the Pharisees and others are not doing the will of the Father. They hear but they do not understand, see both do not perceive who Jesus is. They therefore fulfil the words of Isaiah 6:9-10. As a result, Jesus begins to teach the crowds in parables so that only his family will understand.