Sunan an-Nasai 19060
In-book no 4324أَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا مَالِكٌ، عَنْ عَبْدِ اللَّهِ بْنِ دِينَارٍ، عَنِ ابْنِ عُمَرَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم وَهُوَ عَلَى الْمِنْبَرِ سُئِلَ عَنِ الضَّبِّ فَقَالَ " لاَ آكُلُهُ وَلاَ أُحَرِّمُهُ " .
It was narrated from Ibn 'Umar that: the Messenger of Allah was asked about mastigures when he was on the Minbar and he said? "I do not eat them, but I do not say that they are Haram."