«زَعَمْتُمْ أَنَّ إِخْوَتَكُمْ قُرَيْشٌ ... لَهُمْ إِلْفٌ وَلَيْسَ لَكُمْ إِيلَافُ»
You claimed Quraysh were your brothers … they enjoy established commercial association, while you lack such a bond.
The claim suggests “Was that assertion true?” A direct answer might have been “You were wrong.” Instead it is suppressed, and the contrast of social bonds supplies its force. The omitted answer is conveyed through an argument rather than an overt denial.