Musnad Ahmad 32:1151

Yazid ibn Harun narrated to us, Yahya ibn Sa'id informed us, he said: I heard Anas ibn Malik saying: The Messenger of Allah, may Allah bless him and grant him peace, said: "Shall I not inform you of the best of the houses of the Ansar?" They said: "Yes." He said: "The house of Banu al-Najjar." He said: "Shall I not inform you of those who follow them?" They said: "Yes, O Messenger of Allah." He said: "The house of Banu 'Abd al-Ashhal." "Shall I not inform you of those who follow them?" They said: "Yes, O Messenger of Allah." He said: "The house of Banu al-Harith ibn al-Khazraj." "Shall I not inform you of those who follow them?" They said: "Yes, O Messenger of Allah." He said: "The house of Banu Sa'idah." He said: Then he raised his voice and said: "In every house of the Ansar there is good."