“believe that you have received them, and you will have them.” This verse contains great truth, and great potential to be misunderstood and wrongly applied. Certain faith teachers have taken it to mean that through faith we instantly receive what we ask for, even though it may clearly seem to not be the case, we must nevertheless believe that we have already received what has been asked for. Often, this can lead to unhealthy situations where Christians must pretend that circumstances are not as they are, or feel that they are not having “faith.”
This comes from a misguided understanding of the verse. The second half of the verse should settle any thought as to whether the requests have been received—it assumes they have not. This is why it says, “and you will (future tense) have them.” An understanding of the Greek behind this phrase will further clear things up. To properly understand this verse we must understand the tense of the verb translated “you have received.” It is not the present tense, as the KJV can give the impression with their rendering, “believe that ye receive them.” Rather, the verb is in the aorist (past) tense. So understood literally, the verse would not be asking us to believe we have presently received anything, but to believe that we have already in the past received what we are presently praying for; then, perplexingly, it ends with the promise that if we so believe, we will in the future receive what we believe has already been received before we even asked for it.
How are we to understand this? Why would God put the verb in the aorist tense? The reason is this verse contains as idiom known as the proleptic aorist (under the category of the idiom of the prophetic perfect, see commentary on Eph. 2:6). The proleptic aorist is a form of the figure of speech heterosis, where one tense is used instead of another for emphasis. In this case the aorist tense is used for the future tense, speaking as though a yet future event had already come to pass. Wallace explains the proleptic aorist as follows: “An author sometimes uses the aorist for the future to stress the certainty of the event. It involves a ‘rhetorical transfer’ of a future event as though it were past” (Greek Grammar Beyond the Basics, p. 564). Here in Mark 11:24 the event of receiving what is prayed for is yet future, but it is put in the past tense (“have received”) to emphasize its certainty.
When we understand that this phrase is the idiom of the proleptic aorist, we see that God is not asking us to believe we have already in the past received something we do not really yet have, nor is he asking us to believe we have presently received something we have not yet received; rather, he is asking us to believe we will receive our requests in the future. This saves us from the harm of turning biblical belief into make-believe.