Sunan an-Nasa'i 2996

It was narrated from Muhammad bin Ibrahim At-Taimi that a man amonth them who was called Abdulr-Rahman bin Muadh said:The Messenger of Allah addressed us in Mina, and Allah enabled us to hear hwat he said when we were in our encampments. The Prophet started to teach them their rituals until he reached the Himar (Stoning the pillars), and he said: look for pebbles the size of date stones or fingertips. And he told the Muhajirun to camp in front of the Masjid and the Ansar to camp behind the Masjid