ENOfficial
Abu Haraira (Allah be pleased with him) reported Allah's Messenger (ﷺ) as saying: If any one of you is invited, he should accept (the invitation). In case he is fasting, he should pray (in order to bless the inmates of the house), and if he is not fasting he should eat.
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا حَفْصُ بْنُ غِيَاثٍ، عَنْ هِشَامٍ، عَنِ ابْنِ سِيرِينَ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " إِذَا دُعِيَ أَحَدُكُمْ فَلْيُجِبْ فَإِنْ كَانَ صَائِمًا فَلْيُصَلِّ وَإِنْ كَانَ مُفْطِرًا فَلْيَطْعَمْ ".
sunnah.com