Incredible comments so far -- wonderful things to think about.
If I may, I would just like to point to something that I haven't seen addressed yet and wonder what it might lead to. In Luke 15 there are the three parables, Johnny Groda did a great job of highlighting that the parables were spoken to a mixed group. What I wanted to point to was something that is consistent with the first two, yet different in the third parable. In the first two, of this chapter, the focus of the message is on the subject of losing something and going to great lengths, even risks, to gain it back. The shepherd loses a sheep and leaves his flock to find it. The woman loses a silver coin and sets the others aside and goes through the whole house to find it. Something is lost and then searched for by the one who lost it.
The third, however, has nothing, or no one, searched for when lost. The prodigal son is lost but no 'shepherd' nor 'woman' searches for the son.
In all three, when what was lost was found again there was great celebration. In the first two, what was lost was more obvious, and they were searched for and found by the ones who lost them. In the third, however, what was truly lost? Who truly searched and found it? If all three are reflecting the same point, or issue, then in the third parable we should wonder to find that what was lost was searched for and found by the one who lost it.
Who, then, lost, searched and found?
What, then, was truly lost and then found again?