Abu Haraira (Allah be pleased with him) reported Messenger of Allah 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.

حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، حَدَّثَنَا حَفْصُ بْنُ غِيَاثٍ، عَنْ هِشَامٍ، عَنِ ابْنِ سِيرِينَ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ ﷺ " إِذَا دُعِيَ أَحَدُكُمْ فَلْيُجِبْ فَإِنْ كَانَ صَائِمًا فَلْيُصَلِّ وَإِنْ كَانَ مُفْطِرًا فَلْيَطْعَمْ ".