Jesus' response to the scribal delegation from Jerusalem (3:23-28):
1. Your accusation is illogical. Jesus' response is to point out the nonsensical character of the charge. Why would Satan cooperate with Jesus' attempts to destroy him?
2. Your accusation is unforgivable. The ministry of Jesus marks "the decisive turning point in the contest between good and evil for the control of the world and its people" (France, 169). In their accusation, the Jerusalem scribes are calling good evil and evil good. They are confusing the Spirit of God with the spirit of darkness. Furthermore, not only are they attributing Jesus' power to Satan, but they are accusing him of being demon possessed. This is the charge that lies behind the terrible saying about unforgiveable sin in verses 28-30. (168)
Jesus' response to his family (3:31-35)
Jesus is brusque to the point of rudeness. Never mind the fifth commandment. Never mind what we learn elsewhere in the N.T. that Mary and James were prominent in the Christian movement. Never mind Jesus' attention to his duty as a son in John 19:25-27. Mark's context made family affection a luxury. Mark 13:12 pictures persecution of disciples from their own families. Mark 10:28: "If doing the will of God (verse 35) involves the incomprehension and even hostility of one's family this is a price worth paying." (France, 178)
We aren't told how this scene ends. We assume his words were relayed to his family and they turned around and returned to Nazareth. He went on to teach and heal and exorcize and feed and forgive. He went on to match his will and power against Satan.
This passage doesn't boil down to a simple moral, but it does contain a strong command to give God the glory when we see demons exorcized and evil thwarted. It contains a strong command to get out of the way of Jesus' outrageous and gracious power. Those who impede God's attempts to heal our world are the ones who are out of their (our) minds. Those who stand in the way of God's attempts to redeem relationships are the one with unclean spirits.
As we all know, truth is stranger than fiction. In Sir Arthur Conan Doyle's world, Moriarity dies and Holmes survives despite appearances to the contrary. In the Gospels, Jesus dies and the Satan appears to survive and thrive. Until the great reversal of the resurrection, when we discover that it is the resurrected Jesus who lives and that the power of evil has been mortally wounded.
I know life isn't always cut-and-dried and easy to decipher. But this text in Mark is not focused on life's complexities. It is saying, simply, now is the time to get on the side that will be victorious.
Geoffrey W. Bromiley, Theological Dictionary of the New Testament, edited by Gerhard Kittel and Gerhard Friedrich. William B. Eerdmans Publishing Company.
R.T. France, The Gospel of Mark: A Commentary on the Greek Text. William B. Eerdmans Publishing Company, 2002.