This is indeed an interesting account. But it is not allegorical or symbolic. It is very literal, as much as the spectacular accound of Lazarus' resurrection or Jesus walking on water. Even Jesus talking about transferring "this mountain", the Mount of Olives, was literal. Think about it, is walking on water or resurrecting someone from the dead "easier" than transferring a mountain. No, they are equally difficult. Just as Yoda said to Luke Skywalker ...."size matters not" with the force.
The force Jesus was talking about was the holy spirit. The holy spirit has the power to enable a human to walk on water, raise someone from the dead, shrivel up trees, and transfer mountains.
The context shows that Jesus was teaching his disciples the power of faith and prayer. What's interesting is that power of faith and prayer have never been demonstrated since. But there was one man that did demonstrate an amazing example of faith besides Jesus. It was Peter.
Peter, a human, walked on water, and for some distance according to the account. It wasn't symbolic. It literally happened. And for two thousand years no one since has even come close to such a demonstration. Why? Why spend the time recording the account and several pages of the Bible dedicated to an account that ultimately no one would be able to apply?
We dont know. Is it possible that it was recorded for some purpose to be revealed in the future?
The bottom line is that Jesus was demonstrating the power of the Holy Spirit that humans can tap into through faith and prayer. But how?
No one has shown the ability since Peter.