I've heard the parable of the Prodigal Son preached roughly every 3 years, and so I expect I've heard at least a dozen sermons on the text. Today I heard a new insight I had never heard before.
The parable of the Lost Sheep -- shortly before the Prodigal Son, and part of the same conversation -- describes a shepherd who has 100 sheep until one wanders off and becomes lost. The shepherd seeks the lost sheep tirelessly until he finds it and safely returns the sheep to the flock.
The parable of the Prodigal Son describes a young man who demands his inheritance from his still-living father, leaves home, and squanders his inheritance. After losing everything and nearly starving, he comes back home humbly. While he was still a way off, his father sees him and runs to him and welcomes him.
The sheep who went astray was clueless and foolish. He may not have left intentionally. His separation may have been as simple as not knowing how to find his way back. The shepherd went out looking for him.
The son who went astray acted in coldness, possibly even malice in demanding an inheritance while his father was still alive. The father did not leave everything and go looking for him. Instead, the father waited until the son came back home, and went out to meet him after he had turned back the right direction and was ready to head home.
Those parables show the constancy of God's love and the constancy of the rejoicing in heaven over everyone who returns home safely. They also show different approaches to those who left cluelessly and those who turned away spitefully. The desire to have the lost one back is the same. But for someone who left intentionally, there may be no gain in seeking their return until they want to return. The thing that moves the prodigal son to come back is partly his hardship and his hunger. It's also partly knowing that his father loves him very much, having no doubt his father would welcome him back. The groundwork for the prodigal son's return happened before he left.