It is narrated from Hazrat Abu Dharr (may Allah be pleased with him) that once I asked the Holy Prophet (peace and blessings be upon him): Which was the first mosque built on earth? The Holy Prophet (peace and blessings be upon him) said: Masjid al-Haram. I asked: Then which one? He said: Masjid al-Aqsa. I asked: What was the interval between the two? The Holy Prophet (peace and blessings be upon him) said: Forty years. I asked: Then which mosque? The Holy Prophet (peace and blessings be upon him) said: Then wherever you find the time for prayer, perform it there, for the whole earth is a mosque.