The concept of ʿahd (العهد) involves an established recognition or identification. The commentary elucidates expressions such as «عَهِدْتُ فُلَانًا», referring to familiarity with an individual, and observes that earlier mention can license returning to the referent with al-.
Example: «رَأَيْتُ طَالِبًا ثُمَّ سَأَلْتُ الطَّالِبَ» — “I saw a student and then questioned the student.” Initially the referent is introduced indefinitely; the article in the second clause identifies that same person through the discourse.
Explicit reference avoids repeating a full description. It works only if the earlier referent remains recoverable to the listener.