Can prayer move mountains?

This is a preview of what I am going to speak on this upcoming week at my friend's BCM service. When Jesus says in Matt 21:21 that if we have faith we can move mountains, we can't make a blanket statement across all of our prayer requests and say, "If I have faith it will happen." As a kid I had my heart crushed several times because certain prayer requests weren't answered although I believed beyond a shadow of a doubt that God would answer them. I didn't receive swords, pet dragons, a brother, or anything of the sort despite my impeccable record for having faith as small as a mustard seed.
We have to take verse 21 and see the context of chapter 21 in Jesus' ministry. Jesus entered Jerusalem triumphantly in verses 1-11. In verses 12-17 he cleanses the temple of the money-changers and the salesmen proclaiming that it is a house of prayer, not of thieves. In verses 18-22 he curses a fig tree and teaches on prayer as a kind of afterthought (this afterthought is my main text). From verses 23 and onward to the end, most crucial to understanding what is going on, we see Jesus and the religious leaders arguing over who has the authority to do what. Jesus pronounces a parable on them that builds until verse 43 with the statement "the kingdom of God will be taken away from you and given to a people producing its fruits."
That statement is the most important for understanding the passage on prayer, because we see the teaching on prayer hanging on the end of an incident where Jesus curses a fig tree because there is no fruit. In the scheme of chapter 21, the fig tree becomes an enacted parable where Jesus, seeing the fruitlessness of Israel symbolized in the fruitlessness of the fig tree, curses it as a sign that Israel will soon be cursed and withered, and as he teaches later the "vineyard" or Kingdom of God will be given to another nation.
So the teaching on prayer is right on the heels of this enacted parable. The context of chapter 21 is that Israel is rejecting Jesus' authority, and thereby showing the root of the fruitlessness; rebellion to God. This rebellion will not thwart the kingdom, because it will be given to another nation who will bear fruit unto God. So no sane person in this context would think God is teaching me how to ask and believe in order to get a big mansion or a nice car. This isn't a teaching on "Santa" God.
What it means for the church is that if there is a mountain between you and the fulfillment of Jesus' mission on earth (to bring all nations into Him), then that mountain will be traversed or moved for the sake of Christ. If a mountain of opposition comes against your mission to spread the name of Christ throughout the world, God's inexhaustible power will meet and defeat that mountain in order that Christ's name will be spread.
It doesn't mean I can get what I want from God for no reason except that I asked in faith, it means my requests must be in line with Gospel ends in order for it to apply.
An army is in my way? No big deal, God moves mountains. I don't speak the language? No big deal, God can teach it if I need it now or He can allow me to learn it. A stubborn, fruitless church has possession of all the money to send out missionaries and they are sitting on it? No big deal, God can shake it out of them.

A taste of Christ

The only reasonable ammunition against sin is a clear and strong perception of the glories of Christ through His word and His Spirit. One who is held firmly by this excellence, perceived and enjoyed, will not darken the palette of his or her mind with the lesser pleasures of the flesh as long as the strong and clear fragrance of Christ is present. The temptation to sin many times will not even gravitate the desires of such a person, being mortified to an extent that the pursuits of the world may call, but like water off a ducks back they will roll right off the mind of such a person. If this perception can be maintained through discipline and regular spiritual exercises, the battle against sin is won. The battle is lost when we smudge the glory of Christ on the mirror of our mind with things that do not reflect Him properly. It never happens quickly, but slowly inch by inch the flesh takes back as the affections cool for Christ.
A Christian never runs straight to a "big" sin from this mindset; it is always a little negligence that pulls us away from Christ. Like Peter, we notice the waves, and then we begin to sink. Pride comes before the downfall. The affections cool before sin ensares. Here's where I'm pulling from:

"But each person is tempted when he is lured and enticed by his own desire. Then desire when it has conceived gives birth to sin, and sin when it is fully grown brings forth death."

James 1:14-15

There are three steps to any sin given in these verses: First we have a desire. Then we are tempted and lured by it. Then we sin.

So here's what I'm thinking, If we fight the battle against sin in the desire phase...we can win more easily. There is nothing to lure us and entice us, there is nothing to tempt us. A man living in a house full of half-naked posters of women is not able to purify his desires. His desires have gasoline poured on them at every occasion. Desire must be guarded, and purified. It usually accomadates what it spends the most time around. What you plant in the mind, blooms in the heart. Guard the heart, for it is the wellspring of life.