Hadith 707

Narrated Abu Umamah (RA): The Prophet (ﷺ) 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].