Musnad Abu Ya'la al-Mawsili 164:5

Musa ibn Muhammad ibn Hayyan narrated to us, Abu Bakr al-Hanafi narrated to us, Abdullah ibn Nafi’ narrated to us, al-‘Ala’ ibn ‘Abd al-Rahman informed me, he said: I heard al-Hasan ibn ‘Ali ibn Abi Talib say: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Pray in your houses; do not take them as graves. And do not take my house as a place of celebration (festival). Send blessings and peace upon me, for your blessings and peace reach me wherever you are."