Kathir bin Abdullah al-Muzani (may Allah have mercy on him) narrated from his father, from his grandfather, that in the year of the Confederates (al-Ahzab) the Messenger of Allah (peace and blessings be upon him) marked out the line of the Trench, starting from Ahmar al-Basakhtayn, which was at the edge of Banu Harithah, until it reached al-Madhabih, and he allotted forty cubits to every ten men. Then the Muhajirun and the Ansar disputed over Salman al-Farisi (may Allah have mercy on him), for he was a strong man. The Muhajirun said: Salman is one of us, and the Ansar said: Salman is one of us. At this the Messenger of Allah (peace and blessings be upon him) said: "Salman is one of us, the People of the House (Ahl al-Bayt)."
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 6016