«مَا نَوَالُ الْغَمَامِ وَقْتَ رَبِيعٍ»
What is the cloud's giving in spring—
«كَنَوَالِ الْأَمِيرِ يَوْمَ سَخَاءِ»
compared with the prince's giving on a day of generosity?
The cloud's rain and the prince's gift are both called nawal (“bestowal”), but they are presented as different in worth. The shared category enables the comparison; the explicit distinction produces tafriq. Merely naming two gifts would not be enough.