The Book of Marriage
حَدَّثَنَا ابْنُ نُمَيْرٍ، حَدَّثَنَا عُبَيْدُ اللَّهِ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، أَنَّ النَّبِيَّ صلى الله عليه وسلم قَالَ " إِذَا دُعِيَ أَحَدُكُمْ إِلَى وَلِيمَةِ عُرْسٍ فَلْيُجِبْ " .Ibn Umar (Allah be pleased withthem) reported Allah's Apostle (ﷺ) having said this:When any one of you is invited to a wedding feast, he should accept that
From Sahih Muslim, whose reports the scholars accept as authentic.