Hadith 10:134
‘Abdallah b. ‘Umar reported God’s Messenger as saying, “When one of you is invited to a wedding-feast he must attend it.” In a version by Muslim he said, “He must accept, whether it is a wedding-feast or something of that nature.” (Bukhari and Muslim.)
وَعَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ أَنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ قَالَ: «إِذَا دُعِيَ أَحَدُكُمْ إِلَى الْوَلِيمَةِ فَلْيَأْتِهَا» . مُتَّفَقٌ عَلَيْهِ. وَفِي رِوَايَةٍ لِمُسْلِمٍ: فَلْيُجِبْ عُرْسًا كَانَ أَو نَحوه
Original Reference: Mishkat al-Masabih 3216