They arrived again in Jerusalem, and while Jesus was walking in the temple courts, the chief priests, the teachers of the law and the elders came to him. "By what authority are you doing these things?" they asked. "And who gave you authority to do this?" Jesus replied, "I will ask you one question. Answer me, and I will tell you by what authority I am doing these things. John's baptism - was it from heaven or from men? Tell me!" They discussed it among themselves and said, "If we say, 'From heaven,' he will ask, 'Then why didn't you believe him?' But if we say, 'From men'...." (They feared the people, for everyone held John to be a genuine prophet). So they answered Jesus, "We don't know." Jesus said, "Neither will I tell you by what authority I do these things."
As I read this, I think about James and John. Before Jesus came along, Jesus' cousins were disciples of John the Baptist. John had told them to follow Jesus. So now, when these two cousins of Jesus came into the temple, attending Jesus' class in the temple courts, they must have been aware that Jesus was asking them to pray for a certain cowardly Gentile, the Roman tetrarch ruler of Galilee, Herod. That must have been in their minds when Jesus was saying "forgive".
Now that's getting rather "heavy", as a friend of mine would say. No fooling around here. No pulling punches. This was deadly serious. This exchange shows Jesus was well-prepared. He was serious. He had just told His disciples that the repentant prayer acceptable to God is the prayer offered from a heart that is also overflowing with forgiveness.
I wonder. When Jesus went to the temple to pray, He did so as One called to pray and therefore to forgive the treachery of Herod, Herodias and the leading men of Galilee who, together, had brought about His cousin's death. But now He was being questioned by the religious leaders about His authority. Why were they so scared of Him? Why did they question His authority? Sure they had a responsibility to carefully look at His teaching. All Rabbis were accountable for what they taught. They had a duty to examine Jesus' teaching closely and ask Him questions about what He was saying. But when Mark says they wanted to know the authority Jesus had for doing "these things", it seems as if they are asking about the entry into Jerusalem on the Messianic donkey as well as the cleansing of the temple. These too were an obvious part of Jesus' teaching.
Jesus the Rabbi did not stop teaching when His teaching came under such examination. He took the question of the chief priests, lawyers and elders and used that to teach some more. Here we see Jesus preparing His disciples for their own teaching careers when they would face religious opposition.
Jesus not only refused to answer the trick question the religious leaders put to Him, He explained why. The point was that these religious rulers were more concerned about what the crowd thought than for the true teaching of God. That is what He brought out into the open on this occasion. Think it over. How is it that we know now what the priests, the teachers of the law and the elders were thinking and saying among themselves? Who told Mark what they said to each other? How did Mark and the other gospel writers discover this? Later, it seems, some converted Pharisee or religious leader explained what discussion had taken place among themselves as a result of that confrontation.
Therefore we are also left with a hunch that some were won over to Jesus. Some changed sides and told this part of the story. Mark emphasizes the power of Jesus the Rabbi when He turned this situation into another class for His disciples.
If they were not taking His questions seriously, then Jesus showed them that they cared little for the coming of the Kingdom of God as John had so urgently proclaimed. Those concerned only to give Jesus their stamp of approval were exposed. Jesus answered their question but he knew their tricks. He also knew how they had resisted John's teaching. And so, He took them to task by exposing their fake approach. When they retreated they showed that they were not actually interested in getting an answer to their question. They wanted Jesus to pay attention to them, to respect them as those who might endorse His authority. But having asked them a simply question, Jesus found that they had nothing to say.
In terms of the Kingdom of God, John the Baptist was a success. He stood for the truth even though he lost his life. According to the religion of the scribes, chief priests and elders, John was a big failure. He had lost the power game. They thought they were smart to devise ways of clinging to their puny corner of power while the Romans occupied the land. But it was sham.
Jesus wasn't going to use John's execution as a basis for an armed insurrection. He was not going to forget John's work, and the evil perpetrated by Herod was still alive and well. Jesus forgave and taught His disciples to forgive. That is the point. That is how we understand what Jesus did in the days and weeks leading up to His trial and crucifixion.