Sayyiduna Abu Hurayrah (may Allah be pleased with him) said: "The food of the wedding feast (walimah) to which the rich are invited and the needy are left out is the worst food; yet it is a right, and whoever stays away from the invitation has disobeyed Allah and His Messenger (peace and blessings be upon him)."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصداق / 14523