I said, "O Allah's Messenger (ﷺ)! Which mosque was built first?" He replied, "Al-Masjid-ul-Haram." I asked,"Which (was built) next?" He replied, "Al-Masjid-ul-Aqs-a (i.e. Jerusalem)." I asked, "What was theperiod in between them?" He replied, "Forty (years)." He then added, "Wherever the time for theprayer comes upon you, perform the prayer, for all the earth is a place of worshipping for you."