وَأَلَّفَ بَيْنَ قُلُوبِهِمْ ۚ لَوْ أَنفَقْتَ مَا فِى ٱلْأَرْضِ جَمِيعًا مَّآ أَلَّفْتَ بَيْنَ قُلُوبِهِمْ وَلَـٰكِنَّ ٱللَّهَ أَلَّفَ بَيْنَهُمْ ۚ إِنَّهُۥ عَزِيزٌ حَكِيمٌ
Wa allafa baina quloobihim; law anfaqta maa fil ardi jamee'am maaa allafta baina quloobihim wa laakinnallaaha allafa bainahum; innaahoo 'Azeezun Hakeem
اور ان کے دلوں میں الفت پیدا کردی۔ اور اگر تم دنیا بھر کی دولت خرچ کرتے تب بھی ان کے دلوں میں الفت نہ پیدا کرسکتے۔ مگر خدا ہی نے ان میں الفت ڈال دی۔ بےشک وہ زبردست (اور) حکمت والا ہے
And he joined their hearts together. Had you spent everything on earth, you could not have joined their hearts, but God joined them. Indeed, he is mighty and wise.
Allafa belongs to the family of ulfa, the familiarity that grows between people who have got used to each other; the same root gives the word for a book, pages made to belong together. The first hearers were the Aws and the Khazraj, two tribes of Medina with generations of blood between them. The claim about wealth is exact rather than rhetorical: money can purchase an alliance, and what is named here is the thing it cannot purchase.