It is reported that ‘Amr b. Maymûn said:

The Companions of Allâh’s Messenger – Allâh’s peace and blessings be upon him – used to say, “The mosques are the houses of Allâh on Earth, and it is a right from Allâh that He will honor those who visit Him in [His houses].”

Ibn Al-Mubârak, Al-Zuhd wa Al-Raqâ`iq 4:159.