Sahih (Sahih Muslim)
وَحَدَّثَنِي هَارُونُ بْنُ عَبْدِ اللَّهِ، حَدَّثَنَا حَجَّاجُ بْنُ مُحَمَّدٍ، عَنِ ابْنِ جُرَيْجٍ، أَخْبَرَنِي مُوسَى بْنُ عُقْبَةَ، عَنْ نَافِعٍ، قَالَ سَمِعْتُ عَبْدَ اللَّهِ بْنَ عُمَرَ، يَقُولُ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " أَجِيبُوا هَذِهِ الدَّعْوَةَ إِذَا دُعِيتُمْ لَهَا " . قَالَ وَكَانَ عَبْدُ اللَّهِ بْنُ عُمَرَ يَأْتِي الدَّعْوَةَ فِي الْعُرْسِ وَغَيْرِ الْعُرْسِ وَيَأْتِيهَا وَهُوَ صَائِمٌ .
Nafil reported:I heard Abdullah b. Umar (Allah be pleased with them) narrating that Allah's Messenger (ﷺ) said: Accept the feast when you are invited to it. And Abdullah (b. Umar) used to come to the feast, whether it was a wedding feast or other than that, and he would come there even in the state of fasting