Jesus’s great sermon on the parables can be read as a commentary on his claim that those who do the will of the Father are his brother, sister, and mother. You do not become a brother or sister to Christ through birth, but you become his brother and sister by learning to be his disciple.
As we shall see, the parables become one of the ways in which Jesus trains his disciples to constitute this new family. In particular, he uses parables to help the disciples discern how the kingdom of heaven is established.
The parables, therefore, like the Sermon on the Mount, have always been crucial for the church to imagine the kind of community that we must be in order to survive in a world that assumes that biological kinship is more determinative than our kinship with Christ. The boat on which Jesus sits to deliver his parabolic sermon on the parables is the church that the parables bring into being.
Matthew does not tell us when or why Jesus is in a house, but only that on the same day in which his disciples are accused of breaking the Sabbath Jesus leaves the house and sits beside the sea. As soon as he leaves the house a great crowd gathers around him.
Indeed, the crowd was so great that Jesus must get into a boat in order to address the crowd, who stand on the beach while he sits in the boat to instruct them. We have, therefore, a situation quite similar to that in which Jesus delivered the Sermon on the Mount.
When Jesus delivers the sermon, the crowd hears Jesus, but the disciples are the ones to whom Jesus directs the sermon. In a like manner, Jesus instructs the crowd through some of the parables, but he explains the parables to the disciples because they are the ones who must learn to live in the light of the world revealed by the parables.