Disciples—insiders with Jesus—are those who do the will of God.
For whoever does the will of God, he is My brother and sister and mother.
Mark 3:35
This pericope opens with a summary (Mark 3:7–12): crowds are still following him, looking for what Jesus has to offer in terms of healing of disease and alleviation of affliction—they’re following him for the wrong reasons. The reader is beginning to wonder: If everyone is after Jesus for ulterior motives, is there anybody at all who is truly for Jesus and for his mission, understanding who he is and what he is about? This is the question that the pericope answers.
The mountaintop calling of the Twelve (3:13) is reminiscent of Moses’ trip up Mt. Sinai and the Israelites’ covenanting with God (Exodus 19). This event in Mark 3 was almost a re-enactment of that scene: a new people of God are called and constituted (3:13–19). In a curious paradox, the disciples were appointed “to be with Him” and “to be sent out” by Jesus (3:14). Indeed, one might say that only if one is “with” Jesus can one be sent “from/by” him. The first is a prerequisite for the second. In other words, followers become participants in the mission of Jesus, extending his work, as disciples.
Then, in the subsequent “sandwich” episode (story #1 begun: 3:20–21; story #2 begun and completed: 3:22–30; then story #1 completed: 3:31–35), the answer is conclusively given as to what constitutes an “insider,” a disciple, one who is for Jesus. Notice the play on “inside” and “outside.”
The disciples are inside the house with Jesus (indicated by the plural: “they were not even able to eat,” 3:20)—disciples are physically inside the house. Because they are also with Jesus (3:14), they are morally “insiders.”
Jesus’ family (3:21), go “out” to seize him—the family is physically outside. And their accusation is that Jesus is “out” of his mind—Jesus is accused of being morally “outside.” The irony is that these who are genetically “inside” are physically outside. Accusing Jesus of being “outside,” it is they themselves who are morally “outside.” Later, Jesus’ family are said to be “standing outside” (3:31)—again, they are physically outside (3:32). They are not “with” Jesus, and they are certainly not disciples.
Then come the scribes, ostensibly “insiders” (from Jerusalem, 3:22)—ecclesiastically “inside.” They are likely to be within the house arguing with Jesus—so they are also physically inside. But, accusing Jesus of being in league with Satan, casting “out” demons by Satan (3:22, 23), they imply Jesus is morally “outside.” And Jesus counters, declaring forgiveness for them impossible because they reject the work of God—they are morally cast out eternally. Disciples? Hardly!
Finally we get to the question of what exactly constitutes “insidership”: Jesus’ true/new family is made up of those who do the will of God (3:35). These are the ones who are morally “insiders” with Jesus—the inner circle “around” Jesus (3:34). In contrast to outsiders who fail to recognize Jesus’ person and thus disregard his authority (his Lordship), insiders—those who do the will of God—are the true disciples, appointed by Jesus to be with him and then to be sent by him to extend Jesus’ own mission in the world. And to engage in this activity with all of one’s life is what it means to do the will of God.