Question: "Why does Jesus ask, "Who are my mother and brothers?" in Matthew 12:48?"
Answer: We learn who Jesus’ mother and brothers are from a few separate passages. Of course, Jesus was the Son of God (Matthew 16:16), and His earthly parents were Joseph and Mary (Matthew 1:16). Jesus’ brothers are named in Matthew 13:55: James, Joseph, Simon, and Judas (also known as Jude). He also had sisters, but their names are not given (Matthew 13:55). Not only was Jesus aware of who His family was, but so were those He was talking with in Matthew 12. At first glance it is curious, then, that He would ask, “Who are my mother and brothers?” in Matthew 12:48.
In the context Jesus had healed a man who was blind and mute (Matthew 12:22). The crowds were amazed (Matthew 12:23), but the Pharisees were angered, and they credited the work of Jesus to demonic power (Matthew 12:24). The Pharisees and other leaders had continually rejected Jesus and the gospel He was proclaiming, and this attribution of Jesus’ work to the power of Satan was the breaking point. Jesus pronounced judgment on that generation (Matthew 12:39–45), and from that point on He stopped teaching the multitudes plainly. He instead began to focus on preparing His disciples for their evangelistic task as He began the march toward His sacrifice on the cross.
While Jesus was explaining the severity of that generation’s failure and accountability, Jesus’ mother and brothers were outside, trying to find a way to speak with Him (Matthew 12:46). Someone told Jesus that His mother and brothers were seeking to talk with Him (Matthew 12:47), and He responded by asking, “Who are my mother and brothers?” (Matthew 12:48).
Of course, Jesus knew who His mother and brothers were, but He took that opportunity to present an important truth to His listeners. Those who had rejected Him had considered themselves worthy to enter His kingdom because of their deeds, which they presumed to be righteous. But from the beginning Jesus explained that they had to change their minds (repent) about how they could gain entrance into His kingdom (Matthew 4:17). Instead of relying on their own works or their lineage, they needed to rely on Jesus for their righteousness (Matthew 5—7). Many had assumed that, because they were of Abraham, they were automatically qualified to enter the kingdom (Matthew 3:7–9). But Jesus taught that neither their lineage nor their deeds were enough to get them into the kingdom. Their family relationships were not the ticket into the kingdom. After Jesus had been rejected with finality by those in leadership, and after Jesus had pronounced judgment on that generation, Jesus asks, “Who are my mother and brothers?” In this question, He challenges once again the view that family relationships are enough to provide entrance into the kingdom of God.
Upon asking the question, “Who are my mother and brothers?” Jesus answers it, pointing out His disciples and telling the crowd that His disciples were His mother and brothers (Matthew 12:49). While that initially may have puzzled His listeners, He clarified immediately: “For whoever does the will of my Father in heaven is my brother and sister and mother” (Matthew 12:50). In other words, the relationships that really matter in the eternal scheme of things are those relationships based on rightly relating to God.
Human family relationships are beautiful and necessary blessings, and God is the one who created and provided those relationships. Jesus is not minimizing the importance of family relationships; rather, He is emphasizing that having a right relationship with God by obeying His will is the most important.
How then does one obey His will? As Jesus explained to Nicodemus in John 3, the will of God is to believe in the Son (the word believe occurs 8 times in John 3). Jesus explains later to His disciples that they should believe in Him, even in God (John 14:1), because He is the way, the truth, and the life and no one comes to the Father but through Him (John 14:6). This was the essence of what Jesus had also explained in His Sermon on the Mount (Matthew 5—7)—that people’s associations do not make them righteous, but rather how they relate to God. By asking, “Who are my mother and brothers?” and by His answer to His own question, Jesus drove the point home.