Sahih Muslim Book 4, Hadith Number 1556.

Chapter : Excellence of observing two Rak’ahs in the mosque for one who comes back from a journey.

Abu Murra narrated on the authority of Umm Hani that the Messenger of Allah (may peace be upon him) on the day of the Conquest of Mecca observed in her house eight rak’ahs of prayer in one cloth, its opposite corners having been tied from the opposite sides.