It was narrated from Abu Hurairah:
that the Messenger of Allah said: 'The wedding feast on the first day is an obligation, on the second day is a custom and on the third day is showing off." (JA)
English reference (JA): Vol. 3, Book 9, Hadith 1915 (JA)
Arabic reference (JA): Book 9, Hadith 1990 (JA)