3. the imperfect (present) verb: that which denotes the present or the future.

The particle (ḥarf) has no meaning in and of itself; rather, it points to a meaning in something else, whether it governs what follows—such as the prepositions—or does not, such as the interrogative particles.

There are three kinds of linguistic realities:

1. Lexical: a word employed in the sense for which it was coined in the language, e.g. daʿāʾ applied to the call to prayer.
2. Legal: a word employed in the sense established by the Law, e.g. ṣalāh for the specific words and actions of the ritual prayer.
3. Customary: a word employed in the sense current among people, e.g. dābbah for any four-legged livestock.

The benefit of this classification is that every term is to be understood according to its proper reality in the context where it is used: in linguistic usage it carries its lexical meaning, in juristic usage its legal meaning, and in customary usage its customary meaning.

The command (amr)
A command is a demand to perform an act issued from a position of authority, as in the verse, “Establish the prayer” [al-Anʿām 6:72].

Its principal forms include:

1. The imperative verb, as in: “Establish the prayer” [al-Isrāʾ 17:78].
2. The imperative noun (ism fiʿl al-amr), as when the caller to prayer says: ḥayya ʿalaṣ-ṣalāh (“Come to prayer”).
3. The imperfect verb prefixed with the lām of command, as in: “Let there be among you a community that calls to good, enjoins what is right, and forbids what is wrong” [Āl ʿImrān 3:104].

What the command implies
When the imperative form is free from any contextual indicators that divert it, it denotes that the act commanded is obligatory.