The source's core formulation is:
بِاللَّامِ لِلْإِشَارَةِ إِلَى مَعْهُودٍ
Using al- to point to a referent already established as known.
A maʿhūd (معهود) is something the speaker and listener can identify through prior mention, a shared situation, or a sufficiently clear cue. When «الرَّجُلُ» carries this value, it refers not to men in general but to a particular familiar man.
«جَاءَ رَجُلٌ، فَأَكْرَمْتُ الرَّجُلَ» — “A man came, and I honoured the man.” The second noun returns to the previously mentioned individual. This is a teaching example clarifying anaphoric reference, not a purported verbatim quotation from the textbook.