Sahih Muslim , Book 8, Hadith 3345 (USC-MSA) ⓘ
Ibn Umar (Allah be pleased with them) reported Allah's Apostle having said: When you are invited to a feast (even though it is) the leg of the sheep, you should accept it.
وَحَدَّثَنِي حَرْمَلَةُ بْنُ يَحْيَى، أَخْبَرَنَا ابْنُ وَهْبٍ، حَدَّثَنِي عُمَرُ بْنُ مُحَمَّدٍ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، أَنَّ النَّبِيَّ صلى الله عليه وسلم قَالَ " إِذَا دُعِيتُمْ إِلَى كُرَاعٍ فَأَجِيبُوا " .
also referenced under: Book 16, Hadith 120 (In-Book) & Hadith 1429 (Reference)