As I see it, Jesus’ first words are the key to understanding His words to the chief priests and elders of the Jews.
*28 “What do you think? A man had two sons. And he went to the first and said, ‘Son, go and work in the vineyard today.’
29 And he answered, ‘I will not,’ but afterward he changed his mind and went.
30 And he went to the other son and said the same. And he answered, ‘I go, sir,’ but did not go.
31 Which of the two did the will of his father?” They *said, “The first.” Jesus said to them, “Truly I say to you that the tax collectors and prostitutes will get into the kingdom of God before you.
I think that Jesus is saying that the chief priests and elders tell God that He will do what He asks, but in practice they do not, whereas some tax collectors and prostitutes refuse to do the will of God, but later repent (change their mind) and serve God. Thus, such tax collectors and prostitutes that do so will get into the kingdom (through repentance) before the chief priests and elders who claim to obey God but in practice continue in their disobedience.
1 Corinthians 6
9 Or do you not know that the unrighteous will not inherit the kingdom of God? Do not be deceived; neither fornicators, nor idolaters, nor adulterers, nor effeminate, nor homosexuals, 10 nor thieves, nor the covetous, nor drunkards, nor revilers, nor swindlers, will inherit the kingdom of God.
Paul’s words refer to fornicators, idolaters, adulterers, effeminate, homosexuals, thieves, the covetous, drunkards, revilers, and swindlers who continue in their ways of life without repenting.