أَخْبَرَنَا عَبْدُ اللَّهِ بْنُ سَعِيدٍ ، حَدَّثَنَا عُقْبَةُ بْنُ خَالِدٍ ، عَنْ عُبَيْدِ اللَّهِ ، عَنْ نَافِعٍ ، عَنِ ابْنِ عُمَرَ ، قَالَ : قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ :" إِذَا دُعِيَ أَحَدُكُمْ إِلَى وَلِيمَةٍ، فَلْيُجِبْ ".
قَالَ أَبُو مُحَمَّدٍ : يَنْبَغِي أَنْ يُجِيبَ وَلَيْسَ الْأَكْلُ عَلَيْهِ بِوَاجِبٍ

Abdullah bin Saeed told us, Uqba bin Khalid told us, on the authority of Ubayd Allah, on the authority of Nafi’, on the authority of Ibn Umar, he said: The Messenger of God said: May God’s prayers and peace be upon him: “If one of you is invited to a banquet, he must respond.”
Abu Muhammad said: He should respond, but it is not obligatory to eat at him.