مع التنبيه عليه إن لم يكن مشهورا عند البلغاء
With an indication of borrowing if the source verse is not well known among literary specialists.
An unfamiliar borrowed line may otherwise be mistaken for the later poet's independent wording. A signal such as “as a poet said” clarifies its origin and distinguishes disclosed integration from concealed appropriation.
The condition concerns literary attribution. Putting a borrowed line into a fresh metrical context does not by itself make the original wording the new writer's invention.