The primary reason Jesus told the famous parable of the prodigal son in Luke 15:11-32 wasn’t to air laundry about how screwed up the prodigal son was, or even to elaborate on the details of how he returned home.
Of course these components are vital and very meaningful. Jesus wouldn’t have shared them otherwise. But this story was the third in a series. And the main point of the series was for Jesus to address the Pharisees who accused Him of being too worldly and too friendly with sinners (see Luke 15:1-2).
And to identify an attitude that a lot of Christians seem to have that gets on God’s last nerve.
(By the way, if you just thought to yourself: “God doesn’t have nerves, He’s not a human”, you’re exactly the kind of annoying Christian I’m talking about. Read on, and be infuriated.)

Really, the parable of the prodigal son is all about the other brother. This older brother represents those who can find no joy in the return of someone who was far from God.
He represents the haters who can’t stand to see a church grow, and are filled with envy when God blesses in extraordinary measure.

These folks actually make every attempt to explain away the blessings of God:
“That church is only growing because they’re worldly/shallow/seeker-sensitive”
“All those people can’t really be getting saved… just wait and see how they’re doing in 2 years”
“They don’t care about discipleship, their only concern is conversion”
“There are too many new people here. It’s getting way too big… I don’t know everyone anymore”

Make no mistake: Discipleship is a correct priority. Community is an integral function of the church. Of course we want to make true converts, not manufacture false security.
It’s not that these concerns are invalid.
But the attitude which often underlies them is an attitude that Jesus rebukes.

When I see God bless a church, or hear of many people making professions of faith, I choose to rejoice! I thank God for His favor! I assume the best about what God is doing in other ministries.

When you see the activity of God, don’t be like the other brother.
Kill the fatted calf. Show up at the party with bells on.
Celebrate the good things God is doing.
It sure beats standing outside the door, missing out, and whining:
“But what about me?”