Yes, I am familiar with this theology, and I agree with you that it is not only bogus, but has devastated many believers in the process. The passage in question:
As they were passing by in the morning, they saw the fig tree withered from the roots up. Being reminded, Peter said to Him, "" Rabbi, look, the fig tree which You cursed has withered.'' And Jesus answered saying to them, "" Have faith in God. "" Truly I say to you, whoever says to this mountain, "Be taken up and cast into the sea,' and does not doubt in his heart, but believes that what he says is going to happen, it will be granted him. ""Therefore I say to you, all things for which you pray and ask, believe that you have received them, and they will be granted you. ""Whenever you stand praying, forgive, if you have anything against anyone, so that your Father who is in heaven will also forgive you your transgressions. ["" But if you do not forgive, neither will your Father who is in heaven forgive your transgressions.''] Mark 11:20-26
My first questions are: How did the disciples hear this? Did they ever come to use these words as a promise by which they could become prosperous in the sense we think?
The truth is that we have bent and twisted the verse in question to fit what we would like it to be. But just a quick reading of the book of Acts or any of the epistles reveals either that if the Word-of-Faith doctrine is true, then NONE of the disciples had any real faith (based upon their pathetically impoverished lives), or that this theology has gone so far astray that it totally misunderstands faith altogether. My thought is that those who hold to this desperate theology have simply redefined faith as religious positive thinking combined together with the desires of the flesh.
"... and does not doubt in his heart, but believes that what he says is going to happen,"
To doubt in the heart is what we understand in this world according to everything we have learned through it. This is where the disciples' hearts were as they observed the fig tree that had withered up by the roots after Jesus cursed it. They had no idea whatever how one would come to such a confidence. Because we have grown up in a world that ASSUMES it has figured out how to get around its doubting heart through psychology, we also assume that Jesus' words must be interpreted by our assumption.
Upon hearing these words of Jesus these men did not look upon them as a formula by which to become prosperous, but were once again forced to recognize the inherent difference between themselves and this man who walked and talked with such a powerful confidence. They were constantly being hit with the fact that the life within this man was unlike anything they had known.