Narrated Wahshi ibn Harb:

The Companions of the Prophet ﷺ said: Messenger of Allah ﷺ we eat but we are not satisfied. He said: Perhaps you eat separately. They replied: Yes. He said: If you gather together at your food and mention Allah's name, you will be blessed in it.

Abu Dawud said: If you are invited to a wedding feast before you, do not take it until the owner of the house (i.e. the host) allows you (to eat).

حَدَّثَنَا إِبْرَاهِيمُ بْنُ مُوسَى الرَّازِيُّ، حَدَّثَنَا الْوَلِيدُ بْنُ مُسْلِمٍ، قَالَ حَدَّثَنِي وَحْشِيُّ بْنُ حَرْبٍ، عَنْ أَبِيهِ، عَنْ جَدِّهِ، أَنَّ أَصْحَابَ النَّبِيِّ، ﷺ قَالُوا يَا رَسُولَ اللَّهِ إِنَّا نَأْكُلُ وَلاَ نَشْبَعُ . قَالَ " فَلَعَلَّكُمْ تَفْتَرِقُونَ " . قَالُوا نَعَمْ . قَالَ " فَاجْتَمِعُوا عَلَى طَعَامِكُمْ وَاذْكُرُوا اسْمَ اللَّهِ عَلَيْهِ يُبَارَكْ لَكُمْ فِيهِ " . قَالَ أَبُو دَاوُدَ إِذَا كُنْتَ فِي وَلِيمَةٍ فَوُضِعَ الْعَشَاءُ فَلاَ تَأْكُلْ حَتَّى يَأْذَنَ لَكَ صَاحِبُ الدَّارِ .