Luke 20:4

The baptism of John, was it from heaven, or of men?

The question belongs to Jesus' final confrontation with the temple leaders, when they challenged His authority and He met their challenge with a counter-question. By asking whether John's baptism was from heaven or of men, He pressed them to acknowledge whether John's baptism and mission came from God or merely from human authority. John's baptism was a call to repentance. The people regarded John as a prophet sent from God.

Admitting John's mission was from heaven would force the leaders to face John's testimony that Jesus was the Messiah and to explain why they had not believed him. Denying John's divine mission would cost the leaders the people's respect and risk their anger. Their claim that they did not know exposed their inconsistency and their unwillingness to accept John's teaching and the evidence of divine authority, as well as their fear of the crowd. After they claimed not to know, Jesus refused to answer their question about His authority. Although efforts to reform the corrupt priesthood would prove vain, He still had to give the unbelieving people evidence of His divine mission.