"It was fitting to celebrate and be glad, for this your brother was dead, and is alive; he was lost, and is found." - Luke 15:32 ESV
I've read this passage many times before, and heard it preached from even more. I believe the older brother is the point of all of chapter 15, otherwise Jesus would have stopped the story after verse 24. Yes, Jesus wanted me to understand that he cares about the lost. But he also wanted me to see that when it comes to people I (in the church, religious, believer) haven't cared. And, it's because I haven't realized that spiritually they weren't just "bad" they were dead.
I noticed at the beginning of the chapter the Pharisees and scribes were grumbling because Jesus "receives sinners and eats with them." To the Pharisees and scribes these were dirty people, unclean, unworthy who needed to get their act together.