Allegorizing

I recently read Tim Keller's book The Prodigal God, an exposition and application of the parable of the Good Samaritan. It is hardly possible to read anything of Keller's without being impressed by his zeal for reaching people. But it was also impossible to come away without wondering whether, in this case, the chosen text is able to bear the weight of the book and the book the weight of the text.

In search of the sensus plenior it seems, he ignores Blomberg's moderate-allegorical approach (each parable makes one main point per main character) to find significance that goes way beyond meaning. In addition to the Father, the sinners and the Pharisees we have outreach - 'the father has to go out and invite each of them to come into the feast', the messianic banquet, the cost - atonement, 'home' and other extensions like exile, alienation &, brokenness. Is that all?

Silva makes the point that much allegorical exposition arises from the need for rhetorical effect. (Has the Church Misread the Bible? TOWARDS A DEFINITION OF ALLEGORY,56 )