What does Matthew 21:22 mean?

Seeing a fig tree by the road, he came to it, and found nothing on it but leaves. He said to it, “Let there be no fruit from you forever!” Immediately the fig tree withered away.

When the disciples saw it, they marveled, saying, “How did the fig tree immediately wither away?”

Jesus answered them, “Most certainly I tell you, if you have faith, and don’t doubt, you will not only do what was done to the fig tree, but even if you told this mountain, ‘Be taken up and cast into the sea,’ it would be done.

When he had come into the temple, the chief priests and the elders of the people came to him as he was teaching, and said, “By what authority do you do these things? Who gave you this authority?”

Jesus answered them, “I also will ask you one question, which if you tell me, I likewise will tell you by what authority I do these things.

The baptism of John, where was it from? From heaven or from men?” They reasoned with themselves, saying, “If we say, ‘From heaven,’ he will ask us, ‘Why then did you not believe him?’