Sunan Abi Dawud, Hadith 3731 ⓘ
Jabir reported the Messenger of Allah 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.
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 " .
also referenced under: Hadith 3740 (DarusSalam)