They seem to have put the chapter divisions around the themes in Luke’s reports of Jesus teaching. We’ve had two scary ones and now a wonderful one.
13 was about the stark choice of repenting or facing terrible consequences, like finding the door shut on you, the urgency of repenting… Perhaps this year is the one when the unfruitful tree will be cut down.
Then 14 was teaching about what repenting involves.. Everything. Status, family, your life, your sense of self.. You need to be willing to let it all go.
Now 15 is about the celebration, the love that awaits those who repent, how no sin is too bad, how that just makes the celebration and love greater. And the passionate concern God has for lost souls. A counterbalance to the somewhat coldly pragmatic illustration of the farmer deciding which year to cut the fruitless tree down, now God is compared to someone sweeping and checking every corner of the house for a lost coin, the shepherd risking all for the missing sheep, and carrying it home on his shoulders.. Lovely detail.
And it finishes with the prodigal son who is received with joy despite having squandered half of his father’s resources on silly selfishness. I think it’s important to remember that is not a once only offer. I mean you can only waste half your father’s wealth twice. But that part of the analogy does not hold for God. We also have Jesus’ teaching that you must forgive your brother 70 times 7 times. The focus of this story is the joy the father feels, the love despite the offence.