I said, "O Allah's Messenger (ﷺ)! Which mosque was first built on the surface of the earth?" He said, "Al-Masjid-ul-,Haram (in Mecca)." I said, "Which was built next?" He replied "The mosque of Al-Aqsa (in Jerusalem) ." I said, "What was the period of construction between the two?" He said, "Fortyyears." He added, "Wherever (you may be, and) the prayer time becomes due, perform the prayerthere, for the best thing is to do so (i.e. to offer the prayers in time).