Jesus' Mother and Brothers Come To Hinder Him (8:19-21).
Luke gives no explanation as to why Jesus' mother and brothers come seeking Him, but the fact that they are left on ‘the outside' says all that needs to be said. In some way or another they had come to interfere with His ministry, taking advantage of their relationship with Him. Perhaps He remembered back to another time when His mother had interfered with His ministry when as a young boy He was in the Temple. Then she had had a certain right, even though He had to remind her that He was on earth to do His Father's will. But now she had no right. And nor had His brothers. For God had called Him to His Messianic task.
One purpose of their mention here is as an illustration of those who were not receptive to the word of God, as in the parable. As the chiasmus shows us this incident is closely tied in with this whole passage. Originally Mary had eagerly received the word, but it had clearly become choked within her because of the cares of the world and a worldly-wise attitude. While she recognised His calling, she considered that He needed to be guided rather forcibly on how to fulfil it. Many mothers feel that their sons are never quite up to making final decisions about life, however old they get, and feel therefore that they must make their decisions for them so that they do not make mistakes. Her intentions were no doubt good. But they arose because she did not trust her son to make the right decisions. She had failed to genuinely recognise His Lordship. His brothers were more probably similar to the hardened ground. He was their kid brother Whom they had know all their lives. There was nothing that He could tell them. It would take the resurrection to break them down.
Another side of this is that it was an attempt to divert Jesus from the word. Their aim was to do precisely that. But it was of no avail, for the word was too deeply rooted.
Jesus' Own Family Do Not Receive Him: The Son of Man Is Rejected (8:19-21).
We have already considered these verses in connection with the previous part, but reintroduce them here because they also form the commencement of this new part. Here His own family remain ‘on the outside'. They are not ready to receive Him. They act as a warning that Jesus will not be accepted by everyone. In view of what chapter 9 contains of a continual threat of death this must be seen as significant.