Hadith 3740
Chapter 1: What has been reported about accepting invitations - كتاب الأطعمة
حَدَّثَنَا مُحَمَّدُ بْنُ كَثِيرٍ، أَخْبَرَنَا سُفْيَانُ، عَنْ أَبِي الزُّبَيْرِ، عَنْ جَابِرٍ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " مَنْ دُعِيَ فَلْيُجِبْ فَإِنْ شَاءَ طَعِمَ وَإِنْ شَاءَ تَرَكَ " .
Jabir reported the Messenger of Allah(ﷺ) as sayings:
when one of you is invited to a meal, he must accept. If he wishes he may eat, but if he wishes(to leave), he may leave.
Reference : Sunan Abi Dawud 3740
In-book reference : Book 28, Hadith 5