مَنْ رَاقَبَ النَّاسَ مَاتَ غَمًّا
Whoever anxiously watches others dies of grief.
Comparisons of Bashshār and Salm al-Khāsir involve rhetorical power, concision, and verbal arrangement, while priority and dependence are separate historical questions. Greater artistic force does not by itself prove independent composition.
Before alleging borrowing, ask whether the common element is a generic idea or distinctive formulation, whether wording or only meaning has been taken, and what historical evidence supports the attribution.