When viewed through the eyes of Jesus' first century audience, we see just how many societal taboos were broken in the familiar parable of the Prodigal Son. The father's actions in the parable, with both the returned prodigal and the son who remained at home, were completely contrary to those that would be most expected. Just like that father, God has done the unthinkable on our behalf by taking on the shame and humiliation of the cross, lifting us up and making us worthy.
The Gospel reference is Luke 15:1-3, 11b-32.