Sunan an-Nasa'i, Hadith 4328 ⓘ
It was narrated that Jabir said: "The Messenger of Allah allowed us to eat the flesh or horses but he forbade the flesh of donkeys."
أَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا سُفْيَانُ، عَنْ عَمْرٍو، عَنْ جَابِرٍ، قَالَ أَطْعَمَنَا رَسُولُ اللَّهِ صلى الله عليه وسلم لُحُومَ الْخَيْلِ وَنَهَانَا عَنْ لُحُومِ الْحُمُرِ .
also referenced under: Book 42, Hadith 66 (In-Book) & Volume 5, Book 42, Hadith 4333 (DarusSalam)