Sahih Bukhari Volume 001, Book 008, Hadith Number 377.
Narated By Ishaq : Anas bin Malik said, "My grand-mother Mulaika invited Allah's Apostle for a meal which she herself had prepared. He ate from it and said, 'Get up! I will lead you in the prayer.' " Anas added, "I took my Hasir, washed it with water as it had become dark because of long use and Allah's Apostle stood on it. The orphan (Damira or Ruh) and I aligned behind him and the old lady (Mulaika) stood behind us. Allah's Apostle led us in the prayer and offered two Rak'at and then left."