The speaker may use referential al- (لام العهد) without first naming the referent, if speaker and hearer already know who or what is intended. External reference is fundamentally a matter of recognizability, not mere repetition of a previously uttered word.
If both participants know which local imam they mean, «جَاءَ الإِمَامُ», “the imam came,” can identify that person without his name being repeated. With several plausible imams and no contextual clue, however, identification may fail.
This prepares a distinction from mental reference (العهد الذهني): in external reference a particular referent may be identifiable, whereas mental reference can present a suitable instance of a type without requiring exact external identification.