كتاب النكاح
8  
Marriage
Bulugh al-Maram 1041
Narrated [Abu Hurairah (RA)]:
Allah's Messenger (ﷺ), "When one of you is invited (to a meal) he must accept. If he is fasting he should pray (i.e. make supplication for the host) and if he is not fasting he should eat." [Muslim reported it too].
وَعَنْهُ قَالَ : قَالَ رَسُولُ اَللَّهِ ‏- صلى الله عليه وسلم ‏-{ إِذَا دُعِيَ أَحَدُكُمْ فَلْيُجِبْ ; فَإِنْ كَانَ صَائِمًا فَلْيُصَلِّ , وَإِنْ كَانَ مُفْطِرًا فَلْيُطْعَمْ } أَخْرَجَهُ مُسْلِمٌ أَيْضًا 1‏ .‏
Reference : Bulugh al-Maram 1041
In-book reference : Book 8, Hadith 1041
English translation : Book 8, Hadith 1052
Hadith Text
Reference