"But what do you think about this? A man with two sons told the older boy, 'Son, go out and work in the vineyard today.' The son answered, 'No, I won't go,' but later he changed his mind and went anyway. Then the father told the other son, 'You go,' and he said, 'Yes, sir, I will.' But he didn't go. Which of the two was obeying his father?" They replied, "The first, of course." Then Jesus explained his meaning: "I assure you, corrupt tax collectors and prostitutes will get into the Kingdom of God before you do. For John the Baptist came and showed you the way to life, and you didn't believe him, while tax collectors and prostitutes did. And even when you saw this happening, you refused to turn from your sins and believe him."
In this parable, Jesus speaks to those who believed they were without sin. The nonbelievers, the tax collectors and prostitutes, were accepting the message taught by John the Baptist and were repenting. But the believers were still continuing in their sins. This lesson teaches the value of actions and repentance over stated beliefs.