(16) باب الأَمْرِ بِإِجَابَةِ الدَّاعِي إِلَى دَعْوَةٍ
Ibn Umar (Allah be pleased with them) reported Allah's Apostle (ﷺ) having said:
When you are invited to a feast (even though it is) the leg of the sheep, you should accept it.
Reference: Sahih Muslim 1429 i
In-book reference: Book 16, Hadith 120
USC-MSA web (English) reference(deprecated numbering scheme): Book 8, Hadith 3345