Jesus went to the temple to teach on the days following His entry into Jerusalem riding on a donkey.  

(NASB) Luke 20:1-2 “ON ONE of the days while He was teaching the people in the temple and preaching the gospel, the chief priests and the scribes with the elders confronted Him,
2 and they spoke, saying to Him, ‘Tell us by what authority You are doing these things, or who is the one who gave You this authority?”

  Confrontation speaks from a position of being pious or more knowledgeable or with condemnation with the intent to entrap…I believe that the last possibility was the motive of those men who confronted Jesus.
  Their question was well thought out by their legal minds.  They were “out to get” Jesus.  They wanted to destroy Him, they wanted to kill Him but “they could not find any way to do it, because all the people hung on His words.” (Luke 19:47-48)

  When another points a finger at you with criticism and condemnation, how do you react?  Many people become defensive and seek to state their case.  Jesus did not do that, He did not try to defend His actions of driving out the people buying and selling in the temple precincts.  He made no excuses.
  Jesus answered His accusers with another question.  He asked a question that posed a dilemma for those confrontational men. 
(NASB) Luke 20:3-4 “Jesus answered and said to them, ‘I will also ask you a question, and you tell Me:
4 ‘Was the baptism of John from heaven or from men?’”

  Now those men had a dilemma, how could they answer that question without exposing themselves and their motive?  Remember there was a crowd around Jesus who had been listening to His teaching.  They were listening to this question and answer dialogue.

The dilemma for those men:
(NASB) Luke 20:5-6 “They reasoned among themselves, saying, ‘If we say, ‘From heaven,’ He will say, ‘Why did you not believe him?’
6 ‘But if we say, ‘From men,’ all the people will stone us to death, for they are convinced that John was a prophet.’”

  These men looked at two possible responses and the resulting answers.  And they did not like either of them.  What were they to do?  What was the only solution that would get them out of their dilemma?
(NIV) Luke 20:7 “So they answered, ‘We don’t know where it was from.’”

  Entrapment did not work against Jesus then, and entrapment does not work against Jesus today.  When we (followers of Christ) are entrapped by skeptics, what are we to do?

(NIV) Hebrews 12:2 “Let us fix our eyes on Jesus, the author and perfecter of our faith, who for the joy set before him endured the cross, scorning its shame, and sat down at the right hand of the throne of God.  3Consider him who endured such opposition from sinful men, so that you will not grow weary and lose heart.”