Sahih Muslim , Book 8, Hadith 3341 (USC-MSA) ⓘ
Ibn Umar (Allah be pleased with them) reported Allah's Apostle as saying: When any one of you invites his brother, he (the latter) should accept his wedding feast, or any other like it.
وَحَدَّثَنِي مُحَمَّدُ بْنُ رَافِعٍ، حَدَّثَنَا عَبْدُ الرَّزَّاقِ، أَخْبَرَنَا مَعْمَرٌ، عَنْ أَيُّوبَ، عَنْ نَافِعٍ، أَنَّ ابْنَ عُمَرَ، كَانَ يَقُولُ عَنِ النَّبِيِّ صلى الله عليه وسلم " إِذَا دَعَا أَحَدُكُمْ أَخَاهُ فَلْيُجِبْ عُرْسًا كَانَ أَوْ نَحْوَهُ " .
also referenced under: Book 16, Hadith 116 (In-Book) & Hadith 1429 (Reference)