Jesus had gone into the temple and was teaching and his authority as a religious teacher was questioned by the religious authorities. The chief priests led the temple services and were members of the Sanhedrin and the elders or presbyters weren't.
In return, Jesus asks them a trick question, showing how shrewd he was in understanding the political expediencies at the time and how they mitigated against truth telling as they do today (like Stafford Hospital and phone hacking)
By what authority did John performed his baptism? The religious leaders are unwilling to answer due to the issue's political sensitivity and they get heated with one another because they have been caught out!
Jesus says if you answer me I'll answer you!
Political expediency is nothing new. The religious authorities supported Herod and Pilate. Church, state, government alliance as in Nazi Germany. they were as slippery as snakes! The people thought John was a prophet even though they saw him as mad.
They couldn't answer him because they had no theology just political alliances!
Jesus then uses a parable to illustrate his teaching. In the parable the father is God and the sons, the religious and non religious. Unlike kingdom parables, teaching parables serve to illustrate a truth. The parable of the two sons illustrates the difference between saying and doing. The Pharisees had a real problem with this. They claimed to be mol upright, , tithing mint and cumin, but were hypocrites.
"What do you think?" introduces the parable
The Pharisees knew that despite the special relationship of the Jews to God, they were blessed by their behaviour, not law keeping but doing good!
The so called righteous were Israel's religious leaders but are excluded from Gods kingdom. This is heresy! Blasphemous! Its like saying the Archbishop of Canterbury or the Pope are excluded from Gods Kingdom!.
But the lost unclean sinners like tax collectors and prostitutes, and outcasts are included in the kingdom! They were thousands of religious outcasts in Israel at the time, excluded from its social and religious life. Just like in Britain today!
Jesus however discriminates in favour of the poor! What a message for our Coalition government! Option for the Poor, Liberation theologies of many kind do the same. Positive discrimination! This is rooted in Old Testament theology but not in twenty first century consumer capitalism!