(13) Marriage
كتاب النكاح
(8a) Chapter: The Wedding-feast - Section 1
(8) باب الوليمة - الفصل الأول
Mishkat al-Masabih 3216 
‘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
 مُتَّفَقٌ عَلَيْهِ  (الألباني)حكم :
Reference : Mishkat al-Masabih 3216
In-book reference : Book 13, Hadith 134