I am all for '"you can move mountains" as radical charismatic faith...sometimes.
But as a corrective to the typical "speak to the mountain of your circumstance" interpretation,
Charles R. Page II is helpful.
Many have weighed in as to which mountain of the "this mountain" Jesus spoke of/to is in mind:.
the temple itself (called a mountain in Isaiah 2; Isaiah 56 etc) ,
Temple Mount (Joel Green/John Carroll says Jesus "could only mean" this),
Mount of Olives.
Whichever candidate we choose above (maybe all), the bottom line is the same: the whole temple system is under judgement and must go. On that topic, see N.T. Wright in this video. And this: "For Jesus, the time of the temple is no more.” -Green/ Carroll, “The Death of Jesus in Early Christianity,”).
BUT consider Ryland's first paragraph below: Could the mountain instead/also be Herod's Herodian?
ALSO consider the second paragraph as compelling alternative to "faith that can move mountains."
Could it be "faith and works"?"
Jesus was possibly passing along from Bethpage to the Mount of Olives when this teaching was offered. From that from which they traveled one can see off on the horizon to the south the mountain fortress of the Herodian, Herod the Great's summer palace, some seven miles south of Jerusalem. The Herodian fortress is built inside an artificial mountain that resembles a volcanic cone. To create this structure, Herod the Great had the dirt removed from one hill and piled up on another. It was hollow on the inside, and a very tall fortification wall surrounded its perimeter. This is a mountain that was literally moved!
Furthermore, from the Mount of Olives, on a clear day, the Dead Sea is visible to the southeast. In the West we often misinterpret Jesus' meaning when he says we may move mountains, believing he is taking about magic, or perhaps telekenesis. Yet this is a very practical teaching, conforming to practical Hillelian thought: 'You can do unbelievable things if you are willing to work.' You can move mountains, but you must have faith to put a shovel into the ground and bend your back!
--Jesus and the Land,Charles R. Page II, p127-128
Related: On the Herodian symbolism to Jesus' subversion of empire: