I think it is important to think about what Jesus is and is NOT saying with this statement. I think that the force of this story may get misunderstood by advocates of cheap grace. Jesus is spending a lot of teaching time in Luke 15 to establish God’s great love for all people. And Jesus makes it clear that sinners who repent and turn to God are warmly received by Him. So the focus is on God’s heart and not the degree of the sinner’s sinful condition. God is not MORE happy when a really bad sinner repents than he is if a LESS sinful person comes to Him. Both people are sinners in need of relationship and forgiveness from Him.
We tend to think in this verse that God is not really happy with the ninety-nine righteous persons. Jesus is not saying that. The point of the parables in Luke 15 is comparative. It is not that God has no joy over His obedient children… as if those who stay true to Him somehow bore Him with their obedience. It is more that God’s heart for repentant sinners brings great joy to Him the moment a sinner repents, and truly obedient children will rejoice with Him at that time! In other words, every act of genuine repentance by a sinner gives God great joy. And whether it is one sinner or a hundred sinners who come to Him, God treasures each one!
I have read some current Christian writers (Donald Miller among them in “Blue Like Jazz”) who seem to think that mucking around in our sin is understood and tolerated by God, perhaps even good for us in the long run, and that we can somehow be better people in that behavior. Miller even goes so far as to say that drug-smoking free-love hippies have more understanding of real love and acceptance than many church-goers. These writers look at the end of Luke 15 and the story of the prodigal and sadly seem focused more on the stuff the prodigal son got forgiven of. The point they seem to make is we can do anything and then return to God, and Has has to take us.
But the focus of the parable is not the son’s depravity. It is the Father’s relationship with both sons to whom He offers the same relationship. And both sons need repentance. The prodigal returns in terms of obedience and conformance to the relationship. He does not want to return to sinful indulgence! The tragedy is found in the elder son’s confident trust in his own obedience and his rejection of relationship with a father who forgives awful sinners. When there is joy in heaven when a sinner repents, it is God Who is rejoicing along with His redeemed. He invites us to be part of His heart for sinners. And when we are truly converted, we can’t help but feel the same thrill. God loves all sinners… returning prodigals and obedient sons.