It is narrated from Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) that a man invited him to a walimah. When he arrived, he heard sounds of amusement and idle play and refrained from entering. At this the host asked: What is the matter with you (why did you not come in)? He replied: I heard the Messenger of Allah (peace and blessings be upon him) say: "Whoever adds to the number of a group is counted among them, and whoever is pleased with the deed of a people is considered a partner of the one who does it."
And the hadith of Sayyiduna Umar al-Faruq (may Allah be pleased with him) will come later, in sha'a Allah, in 'Kitab al-Ashribah' (the Book of Drinks).
Hadith Referenceالمطالب العالية بزوائد المسانيد الثمانية / كتاب الوليمة / 1660
Hadith Gradingمحدثین:إسناده ضعيف، موقوف
Hadith Takhrij«حکم الحدیث المطالب العالیہ محققاً تنسیق د. سعد بن ناصر بن عبد العزيز الشَّثري- مکتبہ شاملہ :موقوف، إسناده ضعيف. » «أخرجه إتحاف الخيرة المهرة بزوائد المسانيد العشرة برقم: 3297/1»