What does Luke 5:32 mean?

This is one of several key mission statements Luke gives in his Gospel. The story those statements give is that Jesus calls the lost to repentance, separates the repentant from the resistant, and judges the resistant (Luke 5:32; 7:34; 12:49, 51; 18:8; 19:10). Jesus has already proven—culturally and supernaturally—that He has the authority to forgive sins (Luke 5:17–26). Now, He says that not only is He willing to identify with cultural outcasts and admitted "sinners," but that this is the very reason He came. His ministry is not about gathering the "righteous" but inviting the sinful, leading them to repentance, and making them righteous.

To the Pharisees and scribes, Jesus is eating with traitors, losers and criminals. He's identifying with them and further destroying His reputation as what they would consider an "honorable" man. Rather than mourning their disapproval, Jesus is celebrating God's loving influence. In the story of the one lost sheep, Jesus will say, "Just so, I tell you, there will be more joy in heaven over one sinner who repents than over ninety-nine righteous persons who need no repentance" (Luke 15:7). Levi, and presumably others, have repented; heaven is rejoicing; it is time to eat and drink.

This event may have inspired the parable of the Pharisee and the tax collector. In it, Jesus describes two men who have come to pray at the temple. The Pharisee stands proudly, thanking God by bragging that he is not as sinful as the man next to him. The tax collector lowers his eyes and mourns as he begs God for forgiveness (Luke 18:9–14). As here, it is the man humble enough to know he is a sinner, not the proud man in denial, who receives forgiveness.

Next, Jesus will explain to John the Baptist's disciples (Matthew 9:14) why His disciples don't fast. The bridegroom is here, Jesus says. It is time for celebration, not mourning.