Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) said: "The food of the wedding feast (walimah) on the first and second days is a right." In the narration of al-Sulami: "The food of one day is a right, the food of two days is a Sunnah, and the food of the third day is showing off and reputation; and whoever seeks reputation, Allah will expose him." Al-Sulami did not mention the word "showing off".
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصداق / 14512