Muwatta Malik, Book 58, Hadith 13 (USC-MSA) ⓘ
Yahya related to me from Malik that he heard that the Messenger of Allah, may Allah bless him and grant him peace, said, "Sadaqa to the family of Muhammad is not halal. It is only people's impurities."
حَدَّثَنِي عَنْ مَالِكٍ، أَنَّهُ بَلَغَهُ أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " لاَ تَحِلُّ الصَّدَقَةُ لآلِ مُحَمَّدٍ إِنَّمَا هِيَ أَوْسَاخُ النَّاسِ " .
also referenced under: Book 58, Hadith 1856 (In-Book)