Musnad Ahmad 1018:91

'Abd al-Rahman ibn Mahdi narrated to us, Hammam narrated to us, from Qatadah, from al-Hasan, from 'Abdullah ibn 'Uthman al-Thaqafi, from a man from Thaqif who was one-eyed and called Ma'ruf—and he praised him well—who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "The wedding feast (walimah) is a right. The second day is a kindness (ma'ruf). The third day is showing off and hypocrisy (sum'ah wa riya')."