Mand is a term that B.F. Skinner used to describe a verbal operant in which the response is reinforced by a characteristic consequence and is therefore under the functional control of relevant conditions of deprivation or aversive stimulation.
Chapter three of Skinner's work, Verbal Behavior, discusses a functional relationship called the mand.
For example, a loud knock may be a mand "open the door" and a servant may be called by a hand clap as much as a child might "ask for milk."
This is not to say that mand's function exclusively in favor of the speaker, however; Skinner gives the example of the advice, "Go west!"
[1] The mand form, being under the control of deprivation and stimulation, will vary in energy level.
Prayer might also be analyzed as belonging in one of the above three categories, depending upon one's opinion of the likelihood and mechanism of its answer.