Jesus is teaching. Religious authorities raise doubts. After all, he doesn't come from the right family.
And troubling, their unbelief affects the efficacy of his work.
And also troubling, he doesn't return to the synagogue after this.
How much of this lesson do we want to apply to our modern day? Can our unbelief in the possibility of things getting better keep them from doing so? If we don't trust Jesus' power to heal a situation in church, will we find him in church next time we go?