actually there are a couple of passages that talk about this:
Mark 9:23 (King James Version)
23Jesus said unto him, If thou canst believe, all things are possible to him that believeth.
Matthew 19:26
But Jesus beheld them, and said unto them, With men this is impossible; but with God
all things are possible.
Matthew 21:22
And
all things, whatsoever ye shall ask in prayer, believing, ye shall receive.
Mark 10:27
And Jesus looking upon them saith, With men it is impossible, but not with God: for with God
all things are possible.
That is enough for the moment. If we look at these passages, we find there are actually two prerequisites, 1. it must be in accordance with God's will, or purpose if you will. and 2. you must believe. In fact, I think this verse tells us a host about the whole idea of all things as we see Christ Himself, able to do "all" things and yet only doing what is the Father's will.
Mark 14:36
And he said, Abba, Father,
all things are possible unto thee; take away this cup from me: nevertheless not what I will, but what thou wilt.
See, when we get the totality of scripture in line with the verses being discussed, we realize that "all" includes everything that is in accord with God's will or purpose. But if you don't believe, you are not God's and therefore have no authority over the "all's" of this world.