Sahih Muslim
The Book of Prayers (Kitab Al-Salat)
Book Number: 004 / Hadith Number: 1157
Ibn Buraida narrated it on the authority of his father that a Bedouin came when the Apostle of Allah (may peace be upon him) had completed the morning prayer. He thrust his head in the door of the mosque, and then the hadith (as narrated above) was narrated.