When giving testimony, recording a declaration, or describing an important legal matter, explicitly identifying the subject can be crucial. Leaving it as an ambiguous pronoun or suppressed element may undermine the statement's evidential clarity. The book includes formal witnessing (الإشهاد) and putting an assertion on record (التسجيل) among the reasons for mention.
أو الإشهاد في قضية، أو التسجيل على السامع
Or to establish testimony in a case or record a statement against the addressee.
In «زَيْدٌ أَقَرَّ بِالدَّيْنِ»—“Zayd acknowledged the debt”—naming Zayd helps ensure that the acknowledgment is not attributed to someone else. The concern here is more than style: an explicitly fixed referent can matter for responsibility and proof.