فَاكْتُبُوهُ
So write it down.
The words occur in Qurʾān 2:282 within the directions about deferred debt. The imperative provides practical guidance for safeguarding parties’ rights and avoiding disputes; this is the aspect identified rhetorically as irshād.
فَـ: connects the instruction to its preceding context.
اكْتُبُوا: imperative built on deletion of the final nūn; the plural wāw is its subject.
هُ: object pronoun referring to the debt or transaction under discussion.
Irshād foregrounds the listener’s benefit, prudence and welfare. The communication directs toward sound practice, not merely the speaker’s status.