Sunan an-Nasa'i 4314
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."
أَخْبَرَنَا 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 ‏"‏ ‏.‏