Bulugh al-Maram 7 Business Transactions كتاب البيوع 77

وَعَنْ أَبِي أُمَامَةَ – رضى الله عنه – عَنِ اَلنَّبِيِّ – صلى الله عليه وسلم -قَالَ: { مَنْ شَفَعَ لِأَخِيهِ شَفَاعَةً, فَأَهْدَى لَهُ هَدِيَّةً, فَقَبِلَهَا, فَقَدْ أَتَى بَابًا عَظِيماً مِنْ أَبْوَابِ اَلرِّبَا } رَوَاهُ أَحْمَدُ, وَأَبُو دَاوُدَ, وَفِي إِسْنَادِهِ مَقَالٌ 1 . 1 – ضعيف. رواه أحمد ( 5 / 261 )، وأبو داود ( 3541 ).

Narrated Abu Umamah (RA): The Prophet (صلى الله عليه وسلم) said: “Whoever intercedes for his brother and that one gives him a gift for that (intercession) which he accepts, he has engaged in one of the most terrible types of Riba (undeserving increase in something).” [Reported by Ahmad and Abu Dawud, but one of its narrators’ reliability has been doubted].