Musnad Ahmad 30:1960

Aswad ibn Amir narrated to us, Sharik narrated to us, from Umarah ibn al-Qa'qa', from Abu Zur'ah, from Abu Hurayrah, who said: A man came to the Messenger of Allah, may Allah bless him and grant him peace, and said: "O Messenger of Allah, inform me who is the most deserving of my good companionship?" He said: "Yes, by Allah, you shall be informed." He said: "Who?" He said: "Your mother." He said: "Then who?" He said: "Your mother." He said: "Then who?" He said: "Then your father."