I wonder: but were the pharisees
sincere in their confession of ignorance about the origin of the John's baptism?
So Tertullian:
Christ knew the baptism of John, whence it was. (Luke 20:4) Then why did He ask them, as if He knew not? He knew that the Pharisees would not give Him an answer; then why did He ask in vain? Was it that He might judge them out of their own mouth, or their own heart? Suppose you refer these points to an excuse of the Creator, or to His comparison with Christ; then consider what would have happened if the Pharisees had replied to His question. Suppose their answer to have been, that John's baptism was of men, they would have been immediately stoned to death. (Luke 20:6) Some Marcion, in rivalry to Marcion, would have stood up and said: O most excellent God; how different are his ways from the Creator's! Knowing that men would rush down headlong over it, He placed them actually on the very precipice. For thus do men treat of the Creator respecting His law of the tree. But John's baptism was from heaven. Why, therefore, asks Christ, did you not believe him? (Luke 20:5) He therefore who had wished men to believe John, purposing to censure them because they had not believed him, belonged to Him whose sacrament John was administering. But, at any rate, when He actually met their refusal to say what they thought, with such reprisals as, Neither tell I you by what authority I do these things, (Luke 20:8) He returned evil for evil!
http://www.newadvent.org/fathers/03124.htm
Tertullian assumes already that John's baptism was
''from heaven'' and that therefore it was the correct answer.
But what if the dilemma of the pharisees was really
sincere? That dilemma remembers the fear of the Just people
in Hell to accept the Christ of the Alien God (when the latter descended in Hell after the death on the cross):
was he really the true Christ or only a deception of the creator to tempt them?
So also the pharisees are really
afraid of the demiurge's wrath :
1) if they answer that John was an impostor: the demiurge's crowd would have
stoned them.
2) If they answer that John was truly a prophet of the demiurge, Jesus would have justified the wrath of the demiurge
against them.
Therefore their answer was very sincere: they didn't know the origin of the baptism of John (for fear of the demiurge).
Hence, Jesus is really justified to answer in the same way of the Gnostic Jesus of the Fourth Gospel:
Neither tell I you by what authority I do these things.
...since they were so prisoners of the
fear of their demiurge.