Jesus is again in the temple. Chief priests, scribes, and elders accost him. These are the very folks Jesus predicted who would put him to death (8:31). Jesus is facing his executioners! Their question is more of an attempt to gather evidence in advance of his trial. It’s a kind of verbal cat and mouse.
“Where you get the authority to do all that you do? We readers know the answer but Jesus withholds it instead answering their questions with one of his own. In truth, this is his way of answering their question without saying so in so many words. Jesus’ authority has been a prevalent theme for Mark and here he brings it to a climax. He has authority over Israel.
Jesus answers: “Did the baptism of John come from heaven, or was it of human origin? Answer me” (v.30). His demand for an answer indicates his authority. The logic here is clear.
“Jesus was anointed with the Spirit and power at the time of John’s baptism; John had pointed to him as the Coming One, the one who would act with power, and the voice at the baptism had declared to Jesus himself, in words echoing the royal psalms and prophecies, that he was the true King, God’s own beloved son” (Wright, Mark, 194).
If they had listened to John, or better, because they knew what John had said, these folks argued amongst themselves. Their options were two. Say John was from heaven and they have to admit that his answer is the right one. Say his is just one person’s view and, well, John was popular and authoritative with the people, real popular. They’d have a big problem on their hands.
So they feign ignorance. But it’s not ignorance. It’s a willful rejection of Jesus and pretty much spells the end for official Judaism. And on that basis Jesus refuses to answer them either.