What does Luke 15:23 mean?

The lost son has been found (Luke 15:11–22). Like the parable characters of a shepherd (Luke 15:4) and a woman (Luke 15:8), the father invites others to celebrate (Luke 15:6, 9). The man celebrates with his servants as God celebrates with the angels when someone confesses and turns to Him (Luke 15:7, 10).

This is the final parable about lost things which Jesus teaches to Pharisees and scribes. The religious leaders don't like that Jesus eats with sinners and tax collectors (Luke 15:1–2). The wayward Jews would invite Jesus to dine at their homes at formal banquets. They would invite their friends—equally sinful—to hear Jesus teach. Jesus went willingly, and when the Pharisees objected, He would say, "Those who are well have no need of a physician, but those who are sick. I have not come to call the righteous but sinners to repentance" (Luke 5:31–32).

In the parable of the prodigal son, the father does not accept his wayward son's invitation to a dinner; the father plans the celebration. The idea of the celebration parallels the Jewish understanding of the great feast God will provide when His people are resurrected. The Pharisees can't help but see the connection: these tax collectors and sinners will be with them in the presence of God. If they've been listening, they would know that the repentant sinners may well enjoy the banquet without the Pharisees (Luke 14:24).

Jesus knows the Pharisees can't easily accept this, so He gives them a representative: an older brother who never disobeyed and never thought of taking advantage of his father. They need to understand that the celebration is for the Father and for them. If they truly follow the Father, the sinners are reconciled to them, as well (Luke 15:25–32).

Meat was a luxury in the culture. The "fattened calf" was kept on hand for a special occasion. The father shares it as he shares his joy that his family is restored.