It is in fact derived from the imperative form of Old French oir, to listen.
From the guardian.co.uk
There is no imperative form in the third person, so the subjunctive is used.
From the en.wikipedia.org
A similar entry on the scale of politeness is made by using the imperative form of a polite verb.
From the en.wikipedia.org
There is a negative imperative form used to issue prohibitions.
From the en.wikipedia.org
In the imperative, the form for vos is also derived from the second person plural.
From the en.wikipedia.org
For a command, take the imperative form of the conjugated verb from the infinitive and put it at the beginning of the sentence followed by the corresponding personal pronoun.
From the en.wikipedia.org
The first part, hallelu, is the second-person imperative masculine plural form of the Hebrew verb hallal.
From the en.wikipedia.org
Formulation of the English imperative simply uses the bare infinitive form of the verb.
From the en.wikipedia.org
Whereas the purest form of tactics or engagement are those free of political imperative, the purest form of political policy does not involve military engagement.