لإحضاره أي المسند إليه بعينه
So as to bring the subject itself, precisely identified, before the listener's mind.
Mental presentation (إحضار) here does not mean physically summoning someone into a room. It means evoking or establishing knowledge of the intended referent. Sometimes the listener knows a descriptive category but not which individual is meant; the proper name can specify that individual.
Suppose the listener knows that a learned person came but does not know who. The speaker says «جَاءَنِي زَيْدٌ». The report now concerns Zayd in particular. This is not merely stronger emphasis: it is a different mode of identification.