The Jewish authorities had hoped to trap Jesus (Luke 20:1-2) by causing him to defend himself and admit to something theologically wrong, proving himself to be a lawless fellow seeking to cause trouble for legitimate authority, or admit that he was King of Israel in opposition to Caesar. The least they wished to accomplish was for Jesus to lose face before the people, but they had hoped they could arrest him and punish him themselves or turn him over to Roman authorities to be slain as a rebel.
During the first century AD, rabbis often began their discussions by asking a counter question to one posed to them by another. So, Jesus wasn’t seeking to evade any of the questions put to him (Luke 20:3). Rather, he merely wished to show the question asked (Luke 20:2) was unnecessary. It had been asked and answered before, but they had continually rejected Jesus’ reply. Moreover, this wasn’t the first time the Jewish authorities tried to expose Jesus as a false prophet. Earlier in Luke 11:14-23 they tried to say that Jesus’ miracles were phony, and he cast out demons by the authority of the prince of demons, Beelzebub.
Jesus’ counter question was particularly damaging to the Jewish authorities (Luke 20:4). This is seen in that it was the responsibility of Jewish authorities to, first, determine whether or not a prophet was sent by God and, secondly, expose a false prophet and execute him (Deuteronomy 13:1-11). They neither believed John nor did they publicly claim he was a fraud. Why didn’t they act? John had indorsed Jesus’ Messianic authority (John 1:29-34), so, had the Jewish authorities believed John was a prophet of God, they should have become his disciples. If John endorsed Jesus as the Messiah, they should have done so as well. On the other hand, if they publicly denounced John, even at this time, the people would have stoned them, because the people believed John was a prophet of God. Therefore, no matter how the authorities answered Jesus’ question, it was self incriminating.
Before replying to Jesus’ question, the religious authorities took council together (Luke 20:5-6), wondering what the best reply might be. They claimed to speak for God (Deuteronomy 13:1-5), so, however they might reply to Jesus’ question, it would have been considered God’s own judgment of the matter. However, since the people believed John was a prophet of God, if the religious authorities claimed otherwise, they would put themselves in a place where the people would consider them false teachers, who were opposing the work of God, which he worked through his prophet, John.
On the other hand, if the Jewish authorities did admit John was a prophet of God, then they answered their own question about Jesus’ authority, because John endorsed Jesus as the Messiah. Therefore, if they believed John was a true prophet, they should also accept Jesus as their Messiah, which they didn’t want do. Therefore they were in a quandary of their own making, because they questioned Jesus’ authority.
Seeking to escape the dilemma in which they placed themselves, they simply claimed they didn’t know what to say about John, whether good or evil (Luke 20:7). Hence, they exposed themselves as ignorant leaders, unable to know the ways of God, which they claimed only they knew. Understanding this, we are able to see that these men, who claimed to be defenders of the faith (cf. John 1:19-24), weren’t interested in truth at all. They were motivated by self interest, as are all false teachers. They wanted to accuse Jesus of wrongdoing, but exposed themselves as the real wrongdoers, because they concerned themselves more with what they wanted than with what was true.