Mark 3:20-30 identifies the work of Jesus with the work of God the Holy Spirit. That is, those who reject Christ are also those who blaspheme the Holy Spirit. Mark 3 also testifies to the fact that those who listen to Jesus are listening to God (Mark 3:35). Once again, we are being shown that God is a Triune God: Father, Son, and Holy Spirit.
20 Then he went home, and the crowd gathered again, so that they could not even eat.