...as He was walking in the temple, the chief priests, the scribes, and the elders came to Him. And they said to Him, "By what authority are You doing these things?..."
Picture the scene: Jesus was walking in the Jewish temple in Jerusalem. This was the one and only temple dedicated to the worship of the LORD God. The previous day, he had knocked over the money-changing tables and taught them, "Is it not written: 'My house will be called a house of prayer for all nations'? But you have made it 'a den of robbers'" Mark 11:17. Today, Jesus had returned to the temple. This was the One to whom Solomon spoke, "But will God really dwell on earth with men? The heavens, even the highest heavens, cannot contain you. How much less this temple I have built!" 2 Chronicles 6:18 (Now this temple was the one built after the exile, so it was not the same as the one Solomon dedicated, but it was its replacement a couple hundred years later.) Here was Jesus, walking in his Father's house (Luke 2:49), on the earth as a human being.
And to him come the chief priests, the scribes, and the elders. These were religious leaders. They ask Jesus who gave him authority to do what he has been doing. By "things" I suppose they mean all sorts of things: the miracles, the cleansing of the temple, his authoritative teaching, etc. Some Pharisees thought that his authority came from demons (Matthew 12:24). Other Pharisees said that they knew that he was a teacher sent from God (John 3:2).
How might Jesus have felt when these religious leaders came up to him and asked him this question? On the one hand, he could have been offended. Offended that his creation did not recognize him (John 1:10-11) and even came to trap him with tricky questions that were meant for his harm (Mark 11:18). Did he feel the temptation to reveal himself in some powerful, glorious way? A few years earlier, Satan had tempted him to leap off the temple and be saved miraculously by angels (Luke 4:8-11). Jesus later says, "Do you think I cannot call on my Father, and he will at once put at my disposal more than twelve legions of angels?" (Matthew 26:53) Would he do something like that at this moment, when some of the most powerful and influential Jewish leaders were present and waiting for a response in the house of God? If it were me, I would have been tempted to respond in some way that put them all to shame: "See, I told you! Now do you believe me? Now will you respect me? Now will you recognize me?"
But Jesus didn't respond like that. [He did plainly tell them by what authority he did these things later, after they had put him under oath of the Living God (Matthew 26:62-64). God cannot lie. But on this occasion, he didn't give them an answer.]
Instead of answering right away, Jesus asked them a question first. His response turns and puts the mirror up before them. He asked them a question to reveal their own hearts (much like the Law does). He asks them "John's baptism - was it from heaven, or from men? Tell me!" (Mark 11:30) If they answered one way, they would receive rebuking from Jesus in the sight of the people. If they answered the other way, the people would have had a fit because they believed that John was a prophet. (Mark 11:31-32) Torn between these two fears, they gave no answer. (Mark 11:33) Jesus' words were few, but it was quite an extraordinarily bold demand from the son of a carpenter from Nazareth. When the priests, scribes, and elders refuse to answer, Jesus likewise gives them no answer. Then he begins to speak in parables, teaching the people.
To me, Jesus' response shows incredible self-control as he is obedient to the Father's will in the midst of a provoking and dangerous situation. As a man, his response was very gutsy. As God, his response was very patient. He was teaching, even through this encounter.
On a somewhat related note, why is it that Jesus "kept things" from people? He could have told these religious leaders by whose authority he did these things. He didn't at that time. Sometimes, after healing somebody, he told them not to tell anyone. Why would he do that? I'm not exactly sure, but I did find this interesting:
"Then Jesus said to them, 'When you lift up the Son of Man, then you will know that I am He, and that I do nothing of Myself; but as My Father taught Me, I speak these things." John 8:28
"Now when the centurion saw what had happened, he began praising God, saying, 'Certainly this man was innocent.'" Luke 23:47
"Now the centurion, and those who were with him keeping guard over Jesus, when they saw the earthquake and the things that were happening, became very frightened and said, 'Truly this was the Son of God!'" Matthew 27:54
"When the centurion, who was standing right in front of Him, saw the way He breathed His last, he said, 'Truly this man was the Son of God!'" Mark 15:39