Musnad Ahmad 30:1497

Harun ibn Ma'ruf narrated to us, Abdullah ibn Wahb narrated to us, he said: Ibn Abi Dhi'b informed me, from Abd al-Rahman ibn Mihran, from Abd al-Rahman ibn Sa'd, from Abu Hurairah, that the Messenger of Allah (peace and blessings of Allah be upon him) said: "The farther, then the farther [one's house is], the greater in reward from the mosque."