Ibn Umar (Allah be pleased with him) reported that Allah's Messenger (ﷺ) said:When any one of you is invited to a feast, he should attend it.
حَدَّثَنَا يَحْيَى بْنُ يَحْيَى، قَالَ قَرَأْتُ عَلَى مَالِكٍ عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " إِذَا دُعِيَ أَحَدُكُمْ إِلَى الْوَلِيمَةِ فَلْيَأْتِهَا " .
Muslim
The Book of Marriage • Hadith 112