A statement (khabar) puts forward a proposition; an inshāʾ expression performs a speech act such as commanding, prohibiting, asking or wishing. These forms have recognizable grammatical shapes, but their rhetorical intent can vary.
An imperative may express permission, warning or threat rather than a new universal duty. A question may be designed to make the hearer recognize a fact rather than request unknown information.
The interpreter must keep grammar and communicative purpose separate. The identity of the speaker, the audience and the surrounding argument determine the force of the expression.