Sunan an-Nasa'i, Hadith 4315 ⓘ
It was narrated from Ibn 'Umar that a man said: "O Messenger of Allah what do you think about mastigures?" He said: "I do not eat them but I do not say that they arte Haram."
أَخْبَرَنَا قُتَيْبَةُ، عَنْ مَالِكٍ، عَنْ نَافِعٍ، وَعَبْدِ اللَّهِ بْنِ دِينَارٍ، عَنِ ابْنِ عُمَرَ، أَنَّ رَجُلاً، قَالَ يَا رَسُولَ اللَّهِ مَا تَرَى فِي الضَّبِّ قَالَ " لَسْتُ بِآكِلِهِ وَلاَ مُحَرِّمِهِ " .
also referenced under: Book 42, Hadith 53 (In-Book) & Volume 5, Book 42, Hadith 4320 (DarusSalam)